Text file src/cmd/compile/internal/ssa/_gen/generic.rules

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Simplifications that apply to all backend architectures. As an example, this
     6  // Go source code
     7  //
     8  // y := 0 * x
     9  //
    10  // can be translated into y := 0 without losing any information, which saves a
    11  // pointless multiplication instruction. Other .rules files in this directory
    12  // (for example AMD64.rules) contain rules specific to the architecture in the
    13  // filename. The rules here apply to every architecture.
    14  //
    15  // The code for parsing this file lives in rulegen.go; this file generates
    16  // ssa/rewritegeneric.go.
    17  
    18  // values are specified using the following format:
    19  // (op <type> [auxint] {aux} arg0 arg1 ...)
    20  // the type, aux, and auxint fields are optional
    21  // on the matching side
    22  //  - the type, aux, and auxint fields must match if they are specified.
    23  //  - the first occurrence of a variable defines that variable.  Subsequent
    24  //    uses must match (be == to) the first use.
    25  //  - v is defined to be the value matched.
    26  //  - an additional conditional can be provided after the match pattern with "&&".
    27  // on the generated side
    28  //  - the type of the top-level expression is the same as the one on the left-hand side.
    29  //  - the type of any subexpressions must be specified explicitly (or
    30  //    be specified in the op's type field).
    31  //  - auxint will be 0 if not specified.
    32  //  - aux will be nil if not specified.
    33  
    34  // blocks are specified using the following format:
    35  // (kind controlvalue succ0 succ1 ...)
    36  // controlvalue must be "nil" or a value expression
    37  // succ* fields must be variables
    38  // For now, the generated successors must be a permutation of the matched successors.
    39  
    40  // constant folding
    41  (Trunc16to8  (Const16  [c])) => (Const8   [int8(c)])
    42  (Trunc32to8  (Const32  [c])) => (Const8   [int8(c)])
    43  (Trunc32to16 (Const32  [c])) => (Const16  [int16(c)])
    44  (Trunc64to8  (Const64  [c])) => (Const8   [int8(c)])
    45  (Trunc64to16 (Const64  [c])) => (Const16  [int16(c)])
    46  (Trunc64to32 (Const64  [c])) => (Const32  [int32(c)])
    47  (Cvt64Fto32F (Const64F [c])) => (Const32F [float32(c)])
    48  (Cvt32Fto64F (Const32F [c])) => (Const64F [float64(c)])
    49  (Cvt32to32F  (Const32  [c])) => (Const32F [float32(c)])
    50  (Cvt32to64F  (Const32  [c])) => (Const64F [float64(c)])
    51  (Cvt64to32F  (Const64  [c])) => (Const32F [float32(c)])
    52  (Cvt64to64F  (Const64  [c])) => (Const64F [float64(c)])
    53  (Cvt32Fto32  (Const32F [c])) && c >= -1<<31 && c < 1<<31 => (Const32 [int32(c)])
    54  (Cvt32Fto64  (Const32F [c])) && c >= -1<<63 && c < 1<<63 => (Const64 [int64(c)])
    55  (Cvt64Fto32  (Const64F [c])) && c >= -1<<31 && c < 1<<31 => (Const32 [int32(c)])
    56  (Cvt64Fto64  (Const64F [c])) && c >= -1<<63 && c < 1<<63 => (Const64 [int64(c)])
    57  (Round32F x:(Const32F)) => x
    58  (Round64F x:(Const64F)) => x
    59  (CvtBoolToUint8 (ConstBool [false])) => (Const8 [0])
    60  (CvtBoolToUint8 (ConstBool [true])) => (Const8 [1])
    61  (BitLen64 (Const64 [c])) && config.PtrSize == 8 => (Const64 [int64(bits.Len64(uint64(c)))])
    62  (BitLen32 (Const32 [c])) && config.PtrSize == 8 => (Const64 [int64(bits.Len32(uint32(c)))])
    63  (BitLen16 (Const16 [c])) && config.PtrSize == 8 => (Const64 [int64(bits.Len16(uint16(c)))])
    64  (BitLen8  (Const8  [c])) && config.PtrSize == 8 => (Const64 [int64(bits.Len8(uint8(c)))])
    65  (BitLen64 (Const64 [c])) && config.PtrSize == 4 => (Const32 [int32(bits.Len64(uint64(c)))])
    66  (BitLen32 (Const32 [c])) && config.PtrSize == 4 => (Const32 [int32(bits.Len32(uint32(c)))])
    67  (BitLen16 (Const16 [c])) && config.PtrSize == 4 => (Const32 [int32(bits.Len16(uint16(c)))])
    68  (BitLen8  (Const8  [c])) && config.PtrSize == 4 => (Const32 [int32(bits.Len8(uint8(c)))])
    69  (PopCount64 (Const64 [c])) && config.PtrSize == 8 => (Const64 [int64(bits.OnesCount64(uint64(c)))])
    70  (PopCount32 (Const32 [c])) && config.PtrSize == 8 => (Const64 [int64(bits.OnesCount32(uint32(c)))])
    71  (PopCount16 (Const16 [c])) && config.PtrSize == 8 => (Const64 [int64(bits.OnesCount16(uint16(c)))])
    72  (PopCount8  (Const8  [c])) && config.PtrSize == 8 => (Const64 [int64(bits.OnesCount8(uint8(c)))])
    73  (PopCount64 (Const64 [c])) && config.PtrSize == 4 => (Const32 [int32(bits.OnesCount64(uint64(c)))])
    74  (PopCount32 (Const32 [c])) && config.PtrSize == 4 => (Const32 [int32(bits.OnesCount32(uint32(c)))])
    75  (PopCount16 (Const16 [c])) && config.PtrSize == 4 => (Const32 [int32(bits.OnesCount16(uint16(c)))])
    76  (PopCount8  (Const8  [c])) && config.PtrSize == 4 => (Const32 [int32(bits.OnesCount8(uint8(c)))])
    77  (Bswap64 (Const64 [c])) => (Const64 [int64(bits.ReverseBytes64(uint64(c)))])
    78  (Bswap32 (Const32 [c])) => (Const32 [int32(bits.ReverseBytes32(uint32(c)))])
    79  (Bswap16 (Const16 [c])) => (Const16 [int16(bits.ReverseBytes16(uint16(c)))])
    80  (BitRev64 (Const64 [c])) => (Const64 [int64(bits.Reverse64(uint64(c)))])
    81  (BitRev32 (Const32 [c])) => (Const32 [int32(bits.Reverse32(uint32(c)))])
    82  (BitRev16 (Const16 [c])) => (Const16 [int16(bits.Reverse16(uint16(c)))])
    83  (BitRev8  (Const8  [c])) => (Const8  [int8(bits.Reverse8(uint8(c)))])
    84  (Add64carry (Const64 <t> [x]) (Const64 [y]) (Const64 [c])) && c >= 0 && c <= 1 => (MakeTuple (Const64 <t> [bitsAdd64(x, y, c).sum]) (Const64 <t> [bitsAdd64(x, y, c).carry]))
    85  (Sub64borrow (Const64 <t> [x]) (Const64 [y]) (Const64 [borrowVal])) && borrowVal >= 0 && borrowVal <= 1 => (MakeTuple (Const64 <t> [bitsSub64(x, y, borrowVal).diff]) (Const64 <t> [bitsSub64(x, y, borrowVal).borrow]))
    86  
    87  (RotateLeft64 (Const64 [x]) (Const(64|32) [y])) => (Const64 [int64(bits.RotateLeft64(uint64(x), int(y)))])
    88  (RotateLeft32 (Const32 [x]) (Const(64|32) [y])) => (Const32 [int32(bits.RotateLeft32(uint32(x), int(y)))])
    89  (RotateLeft16 (Const16 [x]) (Const(64|32) [y])) => (Const16 [int16(bits.RotateLeft16(uint16(x), int(y)))])
    90  (RotateLeft8  (Const8  [x]) (Const(64|32) [y])) => (Const8  [int8(bits.RotateLeft8(uint8(x), int(y)))])
    91  
    92  
    93  (Div128u <t> (Const64 [hi]) (Const64 [lo]) (Const64 [y])) && y != 0 && uint64(hi) < uint64(y) => (MakeTuple (Const64 <t.FieldType(0)> [bitsDiv128u(hi, lo, y).quo]) (Const64 <t.FieldType(1)> [bitsDiv128u(hi, lo, y).rem]))
    94  
    95  
    96  (Trunc16to8  (ZeroExt8to16  x)) => x
    97  (Trunc32to8  (ZeroExt8to32  x)) => x
    98  (Trunc32to16 (ZeroExt8to32  x)) => (ZeroExt8to16  x)
    99  (Trunc32to16 (ZeroExt16to32 x)) => x
   100  (Trunc64to8  (ZeroExt8to64  x)) => x
   101  (Trunc64to16 (ZeroExt8to64  x)) => (ZeroExt8to16  x)
   102  (Trunc64to16 (ZeroExt16to64 x)) => x
   103  (Trunc64to32 (ZeroExt8to64  x)) => (ZeroExt8to32  x)
   104  (Trunc64to32 (ZeroExt16to64 x)) => (ZeroExt16to32 x)
   105  (Trunc64to32 (ZeroExt32to64 x)) => x
   106  (Trunc16to8  (SignExt8to16  x)) => x
   107  (Trunc32to8  (SignExt8to32  x)) => x
   108  (Trunc32to16 (SignExt8to32  x)) => (SignExt8to16  x)
   109  (Trunc32to16 (SignExt16to32 x)) => x
   110  (Trunc64to8  (SignExt8to64  x)) => x
   111  (Trunc64to16 (SignExt8to64  x)) => (SignExt8to16  x)
   112  (Trunc64to16 (SignExt16to64 x)) => x
   113  (Trunc64to32 (SignExt8to64  x)) => (SignExt8to32  x)
   114  (Trunc64to32 (SignExt16to64 x)) => (SignExt16to32 x)
   115  (Trunc64to32 (SignExt32to64 x)) => x
   116  
   117  (ZeroExt8to16  (Const8  [c])) => (Const16 [int16( uint8(c))])
   118  (ZeroExt8to32  (Const8  [c])) => (Const32 [int32( uint8(c))])
   119  (ZeroExt8to64  (Const8  [c])) => (Const64 [int64( uint8(c))])
   120  (ZeroExt16to32 (Const16 [c])) => (Const32 [int32(uint16(c))])
   121  (ZeroExt16to64 (Const16 [c])) => (Const64 [int64(uint16(c))])
   122  (ZeroExt32to64 (Const32 [c])) => (Const64 [int64(uint32(c))])
   123  (SignExt8to16  (Const8  [c])) => (Const16 [int16(c)])
   124  (SignExt8to32  (Const8  [c])) => (Const32 [int32(c)])
   125  (SignExt8to64  (Const8  [c])) => (Const64 [int64(c)])
   126  (SignExt16to32 (Const16 [c])) => (Const32 [int32(c)])
   127  (SignExt16to64 (Const16 [c])) => (Const64 [int64(c)])
   128  (SignExt32to64 (Const32 [c])) => (Const64 [int64(c)])
   129  
   130  (Neg8   (Const8   [c])) => (Const8   [-c])
   131  (Neg16  (Const16  [c])) => (Const16  [-c])
   132  (Neg32  (Const32  [c])) => (Const32  [-c])
   133  (Neg64  (Const64  [c])) => (Const64  [-c])
   134  (Neg32F (Const32F [c])) && c != 0 => (Const32F [-c])
   135  (Neg64F (Const64F [c])) && c != 0 => (Const64F [-c])
   136  
   137  (Add8   (Const8 [c])   (Const8 [d]))   => (Const8  [c+d])
   138  (Add16  (Const16 [c])  (Const16 [d]))  => (Const16 [c+d])
   139  (Add32  (Const32 [c])  (Const32 [d]))  => (Const32 [c+d])
   140  (Add64  (Const64 [c])  (Const64 [d]))  => (Const64 [c+d])
   141  (Add32F (Const32F [c]) (Const32F [d])) && c+d == c+d => (Const32F [c+d])
   142  (Add64F (Const64F [c]) (Const64F [d])) && c+d == c+d => (Const64F [c+d])
   143  (AddPtr <t> x (Const64 [c])) => (OffPtr <t> x [c])
   144  (AddPtr <t> x (Const32 [c])) => (OffPtr <t> x [int64(c)])
   145  
   146  (Sub8   (Const8 [c]) (Const8 [d]))     => (Const8 [c-d])
   147  (Sub16  (Const16 [c]) (Const16 [d]))   => (Const16 [c-d])
   148  (Sub32  (Const32 [c]) (Const32 [d]))   => (Const32 [c-d])
   149  (Sub64  (Const64 [c]) (Const64 [d]))   => (Const64 [c-d])
   150  (Sub32F (Const32F [c]) (Const32F [d])) && c-d == c-d => (Const32F [c-d])
   151  (Sub64F (Const64F [c]) (Const64F [d])) && c-d == c-d => (Const64F [c-d])
   152  
   153  (Mul8   (Const8 [c])   (Const8 [d]))   => (Const8  [c*d])
   154  (Mul16  (Const16 [c])  (Const16 [d]))  => (Const16 [c*d])
   155  (Mul32  (Const32 [c])  (Const32 [d]))  => (Const32 [c*d])
   156  (Mul64  (Const64 [c])  (Const64 [d]))  => (Const64 [c*d])
   157  (Mul32F (Const32F [c]) (Const32F [d])) && c*d == c*d => (Const32F [c*d])
   158  (Mul64F (Const64F [c]) (Const64F [d])) && c*d == c*d => (Const64F [c*d])
   159  (Mul32uhilo (Const32 [c]) (Const32 [d])) => (MakeTuple (Const32 <typ.UInt32> [bitsMulU32(c, d).hi]) (Const32 <typ.UInt32> [bitsMulU32(c,d).lo]))
   160  (Mul64uhilo (Const64 [c]) (Const64 [d])) => (MakeTuple (Const64 <typ.UInt64> [bitsMulU64(c, d).hi]) (Const64 <typ.UInt64> [bitsMulU64(c,d).lo]))
   161  (Mul32uover (Const32 [c]) (Const32 [d])) => (MakeTuple (Const32 <typ.UInt32> [bitsMulU32(c, d).lo]) (ConstBool <typ.Bool> [bitsMulU32(c,d).hi != 0]))
   162  (Mul64uover (Const64 [c]) (Const64 [d])) => (MakeTuple (Const64 <typ.UInt64> [bitsMulU64(c, d).lo]) (ConstBool <typ.Bool> [bitsMulU64(c,d).hi != 0]))
   163  
   164  // bits.Mul64(x, 1<<s) for 0 < s < 64.
   165  //   hi:lo = (x >> (64-s), x << s)
   166  (Mul64uhilo x (Const64 [c])) && c > 0 && ssa.IsPowerOfTwo(uint64(c)) =>
   167    (MakeTuple
   168      (Rsh64Ux64 <typ.UInt64> x (Const64 <typ.UInt64> [64 - ssa.Log64u(uint64(c))]))
   169      (Lsh64x64  <typ.UInt64> x (Const64 <typ.UInt64> [ssa.Log64u(uint64(c))])))
   170  
   171  (AndB  (ConstBool [c]) (ConstBool [d])) => (ConstBool [c&&d])
   172  (And8  (Const8    [c]) (Const8    [d])) => (Const8    [c&d])
   173  (And16 (Const16   [c]) (Const16   [d])) => (Const16   [c&d])
   174  (And32 (Const32   [c]) (Const32   [d])) => (Const32   [c&d])
   175  (And64 (Const64   [c]) (Const64   [d])) => (Const64   [c&d])
   176  
   177  (OrB  (ConstBool [c]) (ConstBool [d])) => (ConstBool [c||d])
   178  (Or8  (Const8    [c]) (Const8    [d])) => (Const8    [c|d])
   179  (Or16 (Const16   [c]) (Const16   [d])) => (Const16   [c|d])
   180  (Or32 (Const32   [c]) (Const32   [d])) => (Const32   [c|d])
   181  (Or64 (Const64   [c]) (Const64   [d])) => (Const64   [c|d])
   182  
   183  (Xor8   (Const8  [c])  (Const8  [d]))  => (Const8  [c^d])
   184  (Xor16  (Const16 [c])  (Const16 [d]))  => (Const16 [c^d])
   185  (Xor32  (Const32 [c])  (Const32 [d]))  => (Const32 [c^d])
   186  (Xor64  (Const64 [c])  (Const64 [d]))  => (Const64 [c^d])
   187  
   188  (Ctz64 (Const64 [c])) && config.PtrSize == 4 => (Const32 [int32(ssa.Ntz64(c))])
   189  (Ctz32 (Const32 [c])) && config.PtrSize == 4 => (Const32 [int32(ntz32(c))])
   190  (Ctz16 (Const16 [c])) && config.PtrSize == 4 => (Const32 [int32(ntz16(c))])
   191  (Ctz8  (Const8  [c])) && config.PtrSize == 4 => (Const32 [int32(ntz8(c))])
   192  
   193  (Ctz64 (Const64 [c])) && config.PtrSize == 8 => (Const64 [int64(ssa.Ntz64(c))])
   194  (Ctz32 (Const32 [c])) && config.PtrSize == 8 => (Const64 [int64(ntz32(c))])
   195  (Ctz16 (Const16 [c])) && config.PtrSize == 8 => (Const64 [int64(ntz16(c))])
   196  (Ctz8  (Const8  [c])) && config.PtrSize == 8 => (Const64 [int64(ntz8(c))])
   197  
   198  (Div8   (Const8  [c])  (Const8  [d])) && d != 0 => (Const8  [c/d])
   199  (Div16  (Const16 [c])  (Const16 [d])) && d != 0 => (Const16 [c/d])
   200  (Div32  (Const32 [c])  (Const32 [d])) && d != 0 => (Const32 [c/d])
   201  (Div64  (Const64 [c])  (Const64 [d])) && d != 0 => (Const64 [c/d])
   202  (Div8u  (Const8  [c])  (Const8  [d])) && d != 0 => (Const8  [int8(uint8(c)/uint8(d))])
   203  (Div16u (Const16 [c])  (Const16 [d])) && d != 0 => (Const16 [int16(uint16(c)/uint16(d))])
   204  (Div32u (Const32 [c])  (Const32 [d])) && d != 0 => (Const32 [int32(uint32(c)/uint32(d))])
   205  (Div64u (Const64 [c])  (Const64 [d])) && d != 0 => (Const64 [int64(uint64(c)/uint64(d))])
   206  (Div32F (Const32F [c]) (Const32F [d])) && c/d == c/d => (Const32F [c/d])
   207  (Div64F (Const64F [c]) (Const64F [d])) && c/d == c/d => (Const64F [c/d])
   208  (Div128u <t> (Const64 [0]) lo y) => (MakeTuple (Div64u <t.FieldType(0)> lo y) (Mod64u <t.FieldType(1)> lo y))
   209  
   210  (Not (ConstBool [c])) => (ConstBool [!c])
   211  
   212  (Floor       (Const64F [c])) => (Const64F [math.Floor(c)])
   213  (Ceil        (Const64F [c])) => (Const64F [math.Ceil(c)])
   214  (Trunc       (Const64F [c])) => (Const64F [math.Trunc(c)])
   215  (RoundToEven (Const64F [c])) => (Const64F [math.RoundToEven(c)])
   216  
   217  // Convert x * 1 to x.
   218  (Mul(8|16|32|64)  (Const(8|16|32|64)  [1]) x) => x
   219  (Mul(32|64)uover <t> (Const(32|64) [1]) x) => (MakeTuple x (ConstBool <t.FieldType(1)> [false]))
   220  
   221  // Convert x * -1 to -x.
   222  (Mul(8|16|32|64)  (Const(8|16|32|64)  [-1]) x) => (Neg(8|16|32|64)  x)
   223  
   224  // Convert -x * c to x * -c
   225  (Mul(8|16|32|64) (Const(8|16|32|64) <t> [c]) (Neg(8|16|32|64) x)) => (Mul(8|16|32|64) x (Const(8|16|32|64) <t> [-c]))
   226  
   227  (Mul(8|16|32|64) (Neg(8|16|32|64) x) (Neg(8|16|32|64) y)) => (Mul(8|16|32|64) x y)
   228  
   229  // simplify negative on mul if possible
   230  (Neg(8|16|32|64) (Mul(8|16|32|64) x (Const(8|16|32|64) <t> [c]))) => (Mul(8|16|32|64) x (Const(8|16|32|64) <t> [-c]))
   231  (Neg(8|16|32|64) (Mul(8|16|32|64) x (Neg(8|16|32|64) y))) => (Mul(8|16|32|64) x y)
   232  
   233  // DeMorgan's Laws
   234  (And(8|16|32|64) <t> (Com(8|16|32|64) x) (Com(8|16|32|64) y)) => (Com(8|16|32|64) (Or(8|16|32|64) <t> x y))
   235  (Or(8|16|32|64) <t> (Com(8|16|32|64) x) (Com(8|16|32|64) y)) => (Com(8|16|32|64) (And(8|16|32|64) <t> x y))
   236  
   237  // Absorption laws
   238  (And(8|16|32|64) x (Or(8|16|32|64) x y)) => x
   239  (Or(8|16|32|64) x (And(8|16|32|64) x y)) => x
   240  
   241  (Mod8  (Const8  [c]) (Const8  [d])) && d != 0 => (Const8  [c % d])
   242  (Mod16 (Const16 [c]) (Const16 [d])) && d != 0 => (Const16 [c % d])
   243  (Mod32 (Const32 [c]) (Const32 [d])) && d != 0 => (Const32 [c % d])
   244  (Mod64 (Const64 [c]) (Const64 [d])) && d != 0 => (Const64 [c % d])
   245  
   246  (Mod8u  (Const8 [c])  (Const8  [d])) && d != 0 => (Const8  [int8(uint8(c) % uint8(d))])
   247  (Mod16u (Const16 [c]) (Const16 [d])) && d != 0 => (Const16 [int16(uint16(c) % uint16(d))])
   248  (Mod32u (Const32 [c]) (Const32 [d])) && d != 0 => (Const32 [int32(uint32(c) % uint32(d))])
   249  (Mod64u (Const64 [c]) (Const64 [d])) && d != 0 => (Const64 [int64(uint64(c) % uint64(d))])
   250  
   251  (Lsh64x64  (Const64 [c]) (Const64 [d])) => (Const64 [c << uint64(d)])
   252  (Rsh64x64  (Const64 [c]) (Const64 [d])) => (Const64 [c >> uint64(d)])
   253  (Rsh64Ux64 (Const64 [c]) (Const64 [d])) => (Const64 [int64(uint64(c) >> uint64(d))])
   254  (Lsh32x64  (Const32 [c]) (Const64 [d])) => (Const32 [c << uint64(d)])
   255  (Rsh32x64  (Const32 [c]) (Const64 [d])) => (Const32 [c >> uint64(d)])
   256  (Rsh32Ux64 (Const32 [c]) (Const64 [d])) => (Const32 [int32(uint32(c) >> uint64(d))])
   257  (Lsh16x64  (Const16 [c]) (Const64 [d])) => (Const16 [c << uint64(d)])
   258  (Rsh16x64  (Const16 [c]) (Const64 [d])) => (Const16 [c >> uint64(d)])
   259  (Rsh16Ux64 (Const16 [c]) (Const64 [d])) => (Const16 [int16(uint16(c) >> uint64(d))])
   260  (Lsh8x64   (Const8  [c]) (Const64 [d])) => (Const8  [c << uint64(d)])
   261  (Rsh8x64   (Const8  [c]) (Const64 [d])) => (Const8  [c >> uint64(d)])
   262  (Rsh8Ux64  (Const8  [c]) (Const64 [d])) => (Const8  [int8(uint8(c) >> uint64(d))])
   263  
   264  // Fold IsInBounds when the range of the index cannot exceed the limit.
   265  (IsInBounds (ZeroExt8to32  _) (Const32 [c])) && (1 << 8)  <= c => (ConstBool [true])
   266  (IsInBounds (ZeroExt8to64  _) (Const64 [c])) && (1 << 8)  <= c => (ConstBool [true])
   267  (IsInBounds (ZeroExt16to32 _) (Const32 [c])) && (1 << 16) <= c => (ConstBool [true])
   268  (IsInBounds (ZeroExt16to64 _) (Const64 [c])) && (1 << 16) <= c => (ConstBool [true])
   269  (IsInBounds x x) => (ConstBool [false])
   270  (IsInBounds                (And8  (Const8  [c]) _)  (Const8  [d])) && 0 <= c && c < d => (ConstBool [true])
   271  (IsInBounds (ZeroExt8to16  (And8  (Const8  [c]) _)) (Const16 [d])) && 0 <= c && int16(c) < d => (ConstBool [true])
   272  (IsInBounds (ZeroExt8to32  (And8  (Const8  [c]) _)) (Const32 [d])) && 0 <= c && int32(c) < d => (ConstBool [true])
   273  (IsInBounds (ZeroExt8to64  (And8  (Const8  [c]) _)) (Const64 [d])) && 0 <= c && int64(c) < d => (ConstBool [true])
   274  (IsInBounds                (And16 (Const16 [c]) _)  (Const16 [d])) && 0 <= c && c < d => (ConstBool [true])
   275  (IsInBounds (ZeroExt16to32 (And16 (Const16 [c]) _)) (Const32 [d])) && 0 <= c && int32(c) < d => (ConstBool [true])
   276  (IsInBounds (ZeroExt16to64 (And16 (Const16 [c]) _)) (Const64 [d])) && 0 <= c && int64(c) < d => (ConstBool [true])
   277  (IsInBounds                (And32 (Const32 [c]) _)  (Const32 [d])) && 0 <= c && c < d => (ConstBool [true])
   278  (IsInBounds (ZeroExt32to64 (And32 (Const32 [c]) _)) (Const64 [d])) && 0 <= c && int64(c) < d => (ConstBool [true])
   279  (IsInBounds                (And64 (Const64 [c]) _)  (Const64 [d])) && 0 <= c && c < d => (ConstBool [true])
   280  (IsInBounds (Const32 [c]) (Const32 [d])) => (ConstBool [0 <= c && c < d])
   281  (IsInBounds (Const64 [c]) (Const64 [d])) => (ConstBool [0 <= c && c < d])
   282  // (Mod64u x y) is always between 0 (inclusive) and y (exclusive).
   283  (IsInBounds (Mod32u _ y) y) => (ConstBool [true])
   284  (IsInBounds (Mod64u _ y) y) => (ConstBool [true])
   285  // Right shifting an unsigned number limits its value.
   286  (IsInBounds (ZeroExt8to64  (Rsh8Ux64  _ (Const64 [c]))) (Const64 [d])) && 0 < c && c <  8 && 1<<uint( 8-c)-1 < d => (ConstBool [true])
   287  (IsInBounds (ZeroExt8to32  (Rsh8Ux64  _ (Const64 [c]))) (Const32 [d])) && 0 < c && c <  8 && 1<<uint( 8-c)-1 < d => (ConstBool [true])
   288  (IsInBounds (ZeroExt8to16  (Rsh8Ux64  _ (Const64 [c]))) (Const16 [d])) && 0 < c && c <  8 && 1<<uint( 8-c)-1 < d => (ConstBool [true])
   289  (IsInBounds                (Rsh8Ux64  _ (Const64 [c]))  (Const8  [d])) && 0 < c && c <  8 && 1<<uint( 8-c)-1 < d => (ConstBool [true])
   290  (IsInBounds (ZeroExt16to64 (Rsh16Ux64 _ (Const64 [c]))) (Const64 [d])) && 0 < c && c < 16 && 1<<uint(16-c)-1 < d => (ConstBool [true])
   291  (IsInBounds (ZeroExt16to32 (Rsh16Ux64 _ (Const64 [c]))) (Const32 [d])) && 0 < c && c < 16 && 1<<uint(16-c)-1 < d => (ConstBool [true])
   292  (IsInBounds                (Rsh16Ux64 _ (Const64 [c]))  (Const16 [d])) && 0 < c && c < 16 && 1<<uint(16-c)-1 < d => (ConstBool [true])
   293  (IsInBounds (ZeroExt32to64 (Rsh32Ux64 _ (Const64 [c]))) (Const64 [d])) && 0 < c && c < 32 && 1<<uint(32-c)-1 < d => (ConstBool [true])
   294  (IsInBounds                (Rsh32Ux64 _ (Const64 [c]))  (Const32 [d])) && 0 < c && c < 32 && 1<<uint(32-c)-1 < d => (ConstBool [true])
   295  (IsInBounds                (Rsh64Ux64 _ (Const64 [c]))  (Const64 [d])) && 0 < c && c < 64 && 1<<uint(64-c)-1 < d => (ConstBool [true])
   296  
   297  (IsSliceInBounds x x) => (ConstBool [true])
   298  (IsSliceInBounds (And32 (Const32 [c]) _) (Const32 [d])) && 0 <= c && c <= d => (ConstBool [true])
   299  (IsSliceInBounds (And64 (Const64 [c]) _) (Const64 [d])) && 0 <= c && c <= d => (ConstBool [true])
   300  (IsSliceInBounds (Const32 [0]) _) => (ConstBool [true])
   301  (IsSliceInBounds (Const64 [0]) _) => (ConstBool [true])
   302  (IsSliceInBounds (Const32 [c]) (Const32 [d])) => (ConstBool [0 <= c && c <= d])
   303  (IsSliceInBounds (Const64 [c]) (Const64 [d])) => (ConstBool [0 <= c && c <= d])
   304  (IsSliceInBounds (SliceLen x) (SliceCap x)) => (ConstBool [true])
   305  
   306  (Eq(64|32|16|8|B) x x) => (ConstBool [true])
   307  (EqB (ConstBool [c]) (ConstBool [d])) => (ConstBool [c == d])
   308  (EqB (ConstBool [false]) x) => (Not x)
   309  (EqB (ConstBool [true]) x) => x
   310  (EqB (Not x) y) => (NeqB x y)
   311  
   312  (Neq(64|32|16|8|B) x x) => (ConstBool [false])
   313  (NeqB (ConstBool [c]) (ConstBool [d])) => (ConstBool [c != d])
   314  (NeqB (ConstBool [false]) x) => x
   315  (NeqB (ConstBool [true]) x) => (Not x)
   316  (NeqB (Not x) y) => (EqB x y)
   317  
   318  (CondSelect x _ (ConstBool [true ])) => x
   319  (CondSelect _ y (ConstBool [false])) => y
   320  (CondSelect x x _) => x
   321  
   322  // fold eq / neq between a constant and a compile time bijective operation into the constant.
   323  (Eq(64|32|16|8)  (Const(64|32|16|8) <t> [c]) o:(Add(64|32|16|8) (Const(64|32|16|8) [d]) x)) && o.Uses == 1 => (Eq(64|32|16|8)  (Const(64|32|16|8) <t> [c-d]) x)
   324  (Neq(64|32|16|8) (Const(64|32|16|8) <t> [c]) o:(Add(64|32|16|8) (Const(64|32|16|8) [d]) x)) && o.Uses == 1 => (Neq(64|32|16|8) (Const(64|32|16|8) <t> [c-d]) x)
   325  
   326  (Eq(64|32|16|8)  (Const(64|32|16|8) <t> [c]) o:(Sub(64|32|16|8) x (Const(64|32|16|8) [d]))) && o.Uses == 1 => (Eq(64|32|16|8)  (Const(64|32|16|8) <t> [c+d]) x)
   327  (Neq(64|32|16|8) (Const(64|32|16|8) <t> [c]) o:(Sub(64|32|16|8) x (Const(64|32|16|8) [d]))) && o.Uses == 1 => (Neq(64|32|16|8) (Const(64|32|16|8) <t> [c+d]) x)
   328  
   329  (Eq(64|32|16|8)  (Const(64|32|16|8) <t> [c]) o:(Sub(64|32|16|8) (Const(64|32|16|8) [d]) x)) && o.Uses == 1 => (Eq(64|32|16|8)  (Const(64|32|16|8) <t> [d-c]) x)
   330  (Neq(64|32|16|8) (Const(64|32|16|8) <t> [c]) o:(Sub(64|32|16|8) (Const(64|32|16|8) [d]) x)) && o.Uses == 1 => (Neq(64|32|16|8) (Const(64|32|16|8) <t> [d-c]) x)
   331  
   332  (Eq(64|32|16|8)  (Const(64|32|16|8) <t> [c]) o:(Xor(64|32|16|8) (Const(64|32|16|8) [d]) x)) && o.Uses == 1 => (Eq(64|32|16|8)  (Const(64|32|16|8) <t> [d^c]) x)
   333  (Neq(64|32|16|8) (Const(64|32|16|8) <t> [c]) o:(Xor(64|32|16|8) (Const(64|32|16|8) [d]) x)) && o.Uses == 1 => (Neq(64|32|16|8) (Const(64|32|16|8) <t> [d^c]) x)
   334  
   335  (Eq(64|32|16|8)  (Const(64|32|16|8) <t> [c]) o:(Com(64|32|16|8) x)) && o.Uses == 1 => (Eq(64|32|16|8)  (Const(64|32|16|8) <t> [^c]) x)
   336  (Neq(64|32|16|8) (Const(64|32|16|8) <t> [c]) o:(Com(64|32|16|8) x)) && o.Uses == 1 => (Neq(64|32|16|8) (Const(64|32|16|8) <t> [^c]) x)
   337  
   338  (Eq(64|32|16|8)  (Const(64|32|16|8) <t> [c]) o:(Neg(64|32|16|8) x)) && o.Uses == 1 => (Eq(64|32|16|8)  (Const(64|32|16|8) <t> [-c]) x)
   339  (Neq(64|32|16|8) (Const(64|32|16|8) <t> [c]) o:(Neg(64|32|16|8) x)) && o.Uses == 1 => (Neq(64|32|16|8) (Const(64|32|16|8) <t> [-c]) x)
   340  
   341  ((Eq|Neq)64  (Const64 <t> [c]) o:(Mul64 (Const64 [d]) x)) && uint64(d)%2 == 1 && o.Uses == 1 => ((Eq|Neq)64  (Const64 <t> [int64(uint64(c) *        modularMultiplicativeInverse(uint64(d))) ]) x)
   342  ((Eq|Neq)32  (Const32 <t> [c]) o:(Mul32 (Const32 [d]) x)) && uint32(d)%2 == 1 && o.Uses == 1 => ((Eq|Neq)32  (Const32 <t> [int32(uint32(c) * uint32(modularMultiplicativeInverse(uint64(d))))]) x)
   343  ((Eq|Neq)16  (Const16 <t> [c]) o:(Mul16 (Const16 [d]) x)) && uint16(d)%2 == 1 && o.Uses == 1 => ((Eq|Neq)16  (Const16 <t> [int16(uint16(c) * uint16(modularMultiplicativeInverse(uint64(d))))]) x)
   344  ((Eq|Neq)8   (Const8  <t> [c]) o:(Mul8  (Const8  [d]) x)) && uint8( d)%2 == 1 && o.Uses == 1 => ((Eq|Neq)8   (Const8  <t> [int8( uint8( c) * uint8( modularMultiplicativeInverse(uint64(d))))]) x)
   345  
   346  // signed integer range: ( c <= x && x (<|<=) d ) -> ( unsigned(x-c) (<|<=) unsigned(d-c) )
   347  (AndB (Leq64 (Const64 [c]) x) ((Less|Leq)64 x (Const64 [d]))) && d >= c => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [c])) (Const64 <x.Type> [d-c]))
   348  (AndB (Leq32 (Const32 [c]) x) ((Less|Leq)32 x (Const32 [d]))) && d >= c => ((Less|Leq)32U (Sub32 <x.Type> x (Const32 <x.Type> [c])) (Const32 <x.Type> [d-c]))
   349  (AndB (Leq16 (Const16 [c]) x) ((Less|Leq)16 x (Const16 [d]))) && d >= c => ((Less|Leq)16U (Sub16 <x.Type> x (Const16 <x.Type> [c])) (Const16 <x.Type> [d-c]))
   350  (AndB (Leq8  (Const8  [c]) x) ((Less|Leq)8  x (Const8  [d]))) && d >= c => ((Less|Leq)8U  (Sub8  <x.Type> x (Const8  <x.Type> [c])) (Const8  <x.Type> [d-c]))
   351  
   352  // signed integer range: ( c < x && x (<|<=) d ) -> ( unsigned(x-(c+1)) (<|<=) unsigned(d-(c+1)) )
   353  (AndB (Less64 (Const64 [c]) x) ((Less|Leq)64 x (Const64 [d]))) && d >= c+1 && c+1 > c => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [c+1])) (Const64 <x.Type> [d-c-1]))
   354  (AndB (Less32 (Const32 [c]) x) ((Less|Leq)32 x (Const32 [d]))) && d >= c+1 && c+1 > c => ((Less|Leq)32U (Sub32 <x.Type> x (Const32 <x.Type> [c+1])) (Const32 <x.Type> [d-c-1]))
   355  (AndB (Less16 (Const16 [c]) x) ((Less|Leq)16 x (Const16 [d]))) && d >= c+1 && c+1 > c => ((Less|Leq)16U (Sub16 <x.Type> x (Const16 <x.Type> [c+1])) (Const16 <x.Type> [d-c-1]))
   356  (AndB (Less8  (Const8  [c]) x) ((Less|Leq)8  x (Const8  [d]))) && d >= c+1 && c+1 > c => ((Less|Leq)8U  (Sub8  <x.Type> x (Const8  <x.Type> [c+1])) (Const8  <x.Type> [d-c-1]))
   357  
   358  // unsigned integer range: ( c <= x && x (<|<=) d ) -> ( x-c (<|<=) d-c )
   359  (AndB (Leq64U (Const64 [c]) x) ((Less|Leq)64U x (Const64 [d]))) && uint64(d) >= uint64(c) => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [c])) (Const64 <x.Type> [d-c]))
   360  (AndB (Leq32U (Const32 [c]) x) ((Less|Leq)32U x (Const32 [d]))) && uint32(d) >= uint32(c) => ((Less|Leq)32U (Sub32 <x.Type> x (Const32 <x.Type> [c])) (Const32 <x.Type> [d-c]))
   361  (AndB (Leq16U (Const16 [c]) x) ((Less|Leq)16U x (Const16 [d]))) && uint16(d) >= uint16(c) => ((Less|Leq)16U (Sub16 <x.Type> x (Const16 <x.Type> [c])) (Const16 <x.Type> [d-c]))
   362  (AndB (Leq8U  (Const8  [c]) x) ((Less|Leq)8U  x (Const8  [d]))) && uint8(d)  >= uint8(c)  => ((Less|Leq)8U  (Sub8  <x.Type> x (Const8  <x.Type> [c])) (Const8  <x.Type> [d-c]))
   363  
   364  // unsigned integer range: ( c < x && x (<|<=) d ) -> ( x-(c+1) (<|<=) d-(c+1) )
   365  (AndB (Less64U (Const64 [c]) x) ((Less|Leq)64U x (Const64 [d]))) && uint64(d) >= uint64(c+1) && uint64(c+1) > uint64(c) => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [c+1])) (Const64 <x.Type> [d-c-1]))
   366  (AndB (Less32U (Const32 [c]) x) ((Less|Leq)32U x (Const32 [d]))) && uint32(d) >= uint32(c+1) && uint32(c+1) > uint32(c) => ((Less|Leq)32U (Sub32 <x.Type> x (Const32 <x.Type> [c+1])) (Const32 <x.Type> [d-c-1]))
   367  (AndB (Less16U (Const16 [c]) x) ((Less|Leq)16U x (Const16 [d]))) && uint16(d) >= uint16(c+1) && uint16(c+1) > uint16(c) => ((Less|Leq)16U (Sub16 <x.Type> x (Const16 <x.Type> [c+1])) (Const16 <x.Type> [d-c-1]))
   368  (AndB (Less8U  (Const8  [c]) x) ((Less|Leq)8U  x (Const8  [d]))) && uint8(d)  >= uint8(c+1)  && uint8(c+1)  > uint8(c)  => ((Less|Leq)8U  (Sub8  <x.Type> x (Const8  <x.Type> [c+1]))  (Const8  <x.Type> [d-c-1]))
   369  
   370  // unsigned integer range with a zero lower bound: ( x != 0 && x (<|<=) d ) -> ( x-1 (<|<=) d-1 )
   371  // "x != 0" is the canonical form of the unsigned "0 < x"; see "prefer equalities with zero" below.
   372  (AndB (Neq64 x (Const64 [0])) ((Less|Leq)64U x (Const64 [d]))) && uint64(d) >= 1 => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [1])) (Const64 <x.Type> [d-1]))
   373  (AndB (Neq32 x (Const32 [0])) ((Less|Leq)32U x (Const32 [d]))) && uint32(d) >= 1 => ((Less|Leq)32U (Sub32 <x.Type> x (Const32 <x.Type> [1])) (Const32 <x.Type> [d-1]))
   374  (AndB (Neq16 x (Const16 [0])) ((Less|Leq)16U x (Const16 [d]))) && uint16(d) >= 1 => ((Less|Leq)16U (Sub16 <x.Type> x (Const16 <x.Type> [1])) (Const16 <x.Type> [d-1]))
   375  (AndB (Neq8  x (Const8  [0])) ((Less|Leq)8U  x (Const8  [d]))) && uint8(d)  >= 1 => ((Less|Leq)8U  (Sub8  <x.Type> x (Const8  <x.Type> [1]))  (Const8  <x.Type> [d-1]))
   376  
   377  // signed integer range: ( c (<|<=) x || x < d ) -> ( unsigned(c-d) (<|<=) unsigned(x-d) )
   378  (OrB ((Less|Leq)64 (Const64 [c]) x) (Less64 x (Const64 [d]))) && c >= d => ((Less|Leq)64U (Const64 <x.Type> [c-d]) (Sub64 <x.Type> x (Const64 <x.Type> [d])))
   379  (OrB ((Less|Leq)32 (Const32 [c]) x) (Less32 x (Const32 [d]))) && c >= d => ((Less|Leq)32U (Const32 <x.Type> [c-d]) (Sub32 <x.Type> x (Const32 <x.Type> [d])))
   380  (OrB ((Less|Leq)16 (Const16 [c]) x) (Less16 x (Const16 [d]))) && c >= d => ((Less|Leq)16U (Const16 <x.Type> [c-d]) (Sub16 <x.Type> x (Const16 <x.Type> [d])))
   381  (OrB ((Less|Leq)8  (Const8  [c]) x) (Less8  x (Const8  [d]))) && c >= d => ((Less|Leq)8U  (Const8  <x.Type> [c-d]) (Sub8  <x.Type> x (Const8  <x.Type> [d])))
   382  
   383  // signed integer range: ( c (<|<=) x || x <= d ) -> ( unsigned(c-(d+1)) (<|<=) unsigned(x-(d+1)) )
   384  (OrB ((Less|Leq)64 (Const64 [c]) x) (Leq64 x (Const64 [d]))) && c >= d+1 && d+1 > d => ((Less|Leq)64U (Const64 <x.Type> [c-d-1]) (Sub64 <x.Type> x (Const64 <x.Type> [d+1])))
   385  (OrB ((Less|Leq)32 (Const32 [c]) x) (Leq32 x (Const32 [d]))) && c >= d+1 && d+1 > d => ((Less|Leq)32U (Const32 <x.Type> [c-d-1]) (Sub32 <x.Type> x (Const32 <x.Type> [d+1])))
   386  (OrB ((Less|Leq)16 (Const16 [c]) x) (Leq16 x (Const16 [d]))) && c >= d+1 && d+1 > d => ((Less|Leq)16U (Const16 <x.Type> [c-d-1]) (Sub16 <x.Type> x (Const16 <x.Type> [d+1])))
   387  (OrB ((Less|Leq)8  (Const8  [c]) x) (Leq8  x (Const8  [d]))) && c >= d+1 && d+1 > d => ((Less|Leq)8U  (Const8  <x.Type> [c-d-1]) (Sub8  <x.Type> x (Const8  <x.Type> [d+1])))
   388  
   389  // unsigned integer range: ( c (<|<=) x || x < d ) -> ( c-d (<|<=) x-d )
   390  (OrB ((Less|Leq)64U (Const64 [c]) x) (Less64U x (Const64 [d]))) && uint64(c) >= uint64(d) => ((Less|Leq)64U (Const64 <x.Type> [c-d]) (Sub64 <x.Type> x (Const64 <x.Type> [d])))
   391  (OrB ((Less|Leq)32U (Const32 [c]) x) (Less32U x (Const32 [d]))) && uint32(c) >= uint32(d) => ((Less|Leq)32U (Const32 <x.Type> [c-d]) (Sub32 <x.Type> x (Const32 <x.Type> [d])))
   392  (OrB ((Less|Leq)16U (Const16 [c]) x) (Less16U x (Const16 [d]))) && uint16(c) >= uint16(d) => ((Less|Leq)16U (Const16 <x.Type> [c-d]) (Sub16 <x.Type> x (Const16 <x.Type> [d])))
   393  (OrB ((Less|Leq)8U  (Const8  [c]) x) (Less8U  x (Const8  [d]))) && uint8(c)  >= uint8(d)  => ((Less|Leq)8U  (Const8  <x.Type> [c-d]) (Sub8  <x.Type> x (Const8  <x.Type> [d])))
   394  
   395  // unsigned integer range: ( c (<|<=) x || x <= d ) -> ( c-(d+1) (<|<=) x-(d+1) )
   396  (OrB ((Less|Leq)64U (Const64 [c]) x) (Leq64U x (Const64 [d]))) && uint64(c) >= uint64(d+1) && uint64(d+1) > uint64(d) => ((Less|Leq)64U (Const64 <x.Type> [c-d-1]) (Sub64 <x.Type> x (Const64 <x.Type> [d+1])))
   397  (OrB ((Less|Leq)32U (Const32 [c]) x) (Leq32U x (Const32 [d]))) && uint32(c) >= uint32(d+1) && uint32(d+1) > uint32(d) => ((Less|Leq)32U (Const32 <x.Type> [c-d-1]) (Sub32 <x.Type> x (Const32 <x.Type> [d+1])))
   398  (OrB ((Less|Leq)16U (Const16 [c]) x) (Leq16U x (Const16 [d]))) && uint16(c) >= uint16(d+1) && uint16(d+1) > uint16(d) => ((Less|Leq)16U (Const16 <x.Type> [c-d-1]) (Sub16 <x.Type> x (Const16 <x.Type> [d+1])))
   399  (OrB ((Less|Leq)8U  (Const8  [c]) x) (Leq8U  x (Const8  [d]))) && uint8(c)  >= uint8(d+1)  && uint8(d+1)  > uint8(d)  => ((Less|Leq)8U  (Const8  <x.Type> [c-d-1]) (Sub8  <x.Type> x (Const8  <x.Type> [d+1])))
   400  
   401  // single bit difference: ( x != c && x != d ) -> ( x|(c^d) != c )
   402  (AndB (Neq(64|32|16|8) x cv:(Const(64|32|16|8) [c])) (Neq(64|32|16|8) x (Const(64|32|16|8) [d]))) && c|d == c && ssa.OneBit(c^d) => (Neq(64|32|16|8) (Or(64|32|16|8) <x.Type> x (Const(64|32|16|8) <x.Type> [c^d])) cv)
   403  
   404  // single bit difference: ( x == c || x == d ) -> ( x|(c^d) == c )
   405  (OrB (Eq(64|32|16|8) x cv:(Const(64|32|16|8) [c])) (Eq(64|32|16|8) x (Const(64|32|16|8) [d]))) && c|d == c && ssa.OneBit(c^d) => (Eq(64|32|16|8) (Or(64|32|16|8) <x.Type> x (Const(64|32|16|8) <x.Type> [c^d])) cv)
   406  
   407  // NaN check: ( x != x || x (>|>=|<|<=) c ) -> ( !(c (>=|>|<=|<) x) )
   408  (OrB (Neq64F x x) ((Less|Leq)64F x y:(Const64F [c]))) => (Not ((Leq|Less)64F y x))
   409  (OrB (Neq64F x x) ((Less|Leq)64F y:(Const64F [c]) x)) => (Not ((Leq|Less)64F x y))
   410  (OrB (Neq32F x x) ((Less|Leq)32F x y:(Const32F [c]))) => (Not ((Leq|Less)32F y x))
   411  (OrB (Neq32F x x) ((Less|Leq)32F y:(Const32F [c]) x)) => (Not ((Leq|Less)32F x y))
   412  
   413  // NaN check: ( x != x || Abs(x) (>|>=|<|<=) c ) -> ( !(c (>=|>|<=|<) Abs(x) )
   414  (OrB (Neq64F x x) ((Less|Leq)64F abs:(Abs x) y:(Const64F [c]))) => (Not ((Leq|Less)64F y abs))
   415  (OrB (Neq64F x x) ((Less|Leq)64F y:(Const64F [c]) abs:(Abs x))) => (Not ((Leq|Less)64F abs y))
   416  
   417  // NaN check: ( x != x || -x (>|>=|<|<=) c ) -> ( !(c (>=|>|<=|<) -x) )
   418  (OrB (Neq64F x x) ((Less|Leq)64F neg:(Neg64F x) y:(Const64F [c]))) => (Not ((Leq|Less)64F y neg))
   419  (OrB (Neq64F x x) ((Less|Leq)64F y:(Const64F [c]) neg:(Neg64F x))) => (Not ((Leq|Less)64F neg y))
   420  (OrB (Neq32F x x) ((Less|Leq)32F neg:(Neg32F x) y:(Const32F [c]))) => (Not ((Leq|Less)32F y neg))
   421  (OrB (Neq32F x x) ((Less|Leq)32F y:(Const32F [c]) neg:(Neg32F x))) => (Not ((Leq|Less)32F neg y))
   422  
   423  // Canonicalize x-const to x+(-const)
   424  (Sub64 x (Const64 <t> [c])) && x.Op != ssaop.OpConst64 => (Add64 (Const64 <t> [-c]) x)
   425  (Sub32 x (Const32 <t> [c])) && x.Op != ssaop.OpConst32 => (Add32 (Const32 <t> [-c]) x)
   426  (Sub16 x (Const16 <t> [c])) && x.Op != ssaop.OpConst16 => (Add16 (Const16 <t> [-c]) x)
   427  (Sub8  x (Const8  <t> [c])) && x.Op != ssaop.OpConst8  => (Add8  (Const8  <t> [-c]) x)
   428  
   429  // fold negation into comparison operators
   430  (Not (Eq(64|32|16|8|B|Ptr|64F|32F) x y)) => (Neq(64|32|16|8|B|Ptr|64F|32F) x y)
   431  (Not (Neq(64|32|16|8|B|Ptr|64F|32F) x y)) => (Eq(64|32|16|8|B|Ptr|64F|32F) x y)
   432  
   433  (Not (Less(64|32|16|8) x y)) => (Leq(64|32|16|8) y x)
   434  (Not (Less(64|32|16|8)U x y)) => (Leq(64|32|16|8)U y x)
   435  (Not (Leq(64|32|16|8) x y)) => (Less(64|32|16|8) y x)
   436  (Not (Leq(64|32|16|8)U x y)) => (Less(64|32|16|8)U y x)
   437  
   438  // Distribute multiplication c * (d+x) -> c*d + c*x. Useful for:
   439  // a[i].b = ...; a[i+1].b = ...
   440  // The !isPowerOfTwo is a kludge to keep a[i+1] using an index by a multiply,
   441  // which turns into an index by a shift, which can use a shifted operand on ARM systems.
   442  (Mul64 (Const64 <t> [c]) (Add64 <t> (Const64 <t> [d]) x)) && !ssa.IsPowerOfTwo(c) =>
   443    (Add64 (Const64 <t> [c*d]) (Mul64 <t> (Const64 <t> [c]) x))
   444  (Mul32 (Const32 <t> [c]) (Add32 <t> (Const32 <t> [d]) x)) && !ssa.IsPowerOfTwo(c) =>
   445    (Add32 (Const32 <t> [c*d]) (Mul32 <t> (Const32 <t> [c]) x))
   446  (Mul16 (Const16 <t> [c]) (Add16 <t> (Const16 <t> [d]) x)) && !ssa.IsPowerOfTwo(c) =>
   447    (Add16 (Const16 <t> [c*d]) (Mul16 <t> (Const16 <t> [c]) x))
   448  (Mul8 (Const8 <t> [c]) (Add8 <t> (Const8 <t> [d]) x)) && !ssa.IsPowerOfTwo(c) =>
   449    (Add8 (Const8 <t> [c*d]) (Mul8 <t> (Const8 <t> [c]) x))
   450  
   451  // Rewrite x*y ± x*z  to  x*(y±z)
   452  (Add(64|32|16|8) <t> (Mul(64|32|16|8) x y) (Mul(64|32|16|8) x z))
   453  	=> (Mul(64|32|16|8) x (Add(64|32|16|8) <t> y z))
   454  (Sub(64|32|16|8) <t> (Mul(64|32|16|8) x y) (Mul(64|32|16|8) x z))
   455  	=> (Mul(64|32|16|8) x (Sub(64|32|16|8) <t> y z))
   456  
   457  // Canonicalize x+x to x << 1.
   458  // This is often slower since most CPUs have more adders than shifters, but it can enable other optimizations.
   459  // Arches who care about this like AMD64 convert x << 1 back to x+x in their arch-specific rules which is useful anyhow.
   460  (Add(64|32|16|8) x x) => (Lsh(64|32|16|8)x64 x (Const64 <types.Types[types.TUINT64]> [1]))
   461  
   462  // rewrite shifts of 8/16/32 bit consts into 64 bit consts to reduce
   463  // the number of the other rewrite rules for const shifts
   464  (Lsh64x32  x (Const32 [c])) => (Lsh64x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint32(c))]))
   465  (Lsh64x16  x (Const16 [c])) => (Lsh64x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint16(c))]))
   466  (Lsh64x8   x (Const8  [c])) => (Lsh64x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint8(c))]))
   467  (Rsh64x32  x (Const32 [c])) => (Rsh64x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint32(c))]))
   468  (Rsh64x16  x (Const16 [c])) => (Rsh64x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint16(c))]))
   469  (Rsh64x8   x (Const8  [c])) => (Rsh64x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint8(c))]))
   470  (Rsh64Ux32 x (Const32 [c])) => (Rsh64Ux64 x (Const64 <types.Types[types.TUINT64]> [int64(uint32(c))]))
   471  (Rsh64Ux16 x (Const16 [c])) => (Rsh64Ux64 x (Const64 <types.Types[types.TUINT64]> [int64(uint16(c))]))
   472  (Rsh64Ux8  x (Const8  [c])) => (Rsh64Ux64 x (Const64 <types.Types[types.TUINT64]> [int64(uint8(c))]))
   473  
   474  (Lsh32x32  x (Const32 [c])) => (Lsh32x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint32(c))]))
   475  (Lsh32x16  x (Const16 [c])) => (Lsh32x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint16(c))]))
   476  (Lsh32x8   x (Const8  [c])) => (Lsh32x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint8(c))]))
   477  (Rsh32x32  x (Const32 [c])) => (Rsh32x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint32(c))]))
   478  (Rsh32x16  x (Const16 [c])) => (Rsh32x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint16(c))]))
   479  (Rsh32x8   x (Const8  [c])) => (Rsh32x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint8(c))]))
   480  (Rsh32Ux32 x (Const32 [c])) => (Rsh32Ux64 x (Const64 <types.Types[types.TUINT64]> [int64(uint32(c))]))
   481  (Rsh32Ux16 x (Const16 [c])) => (Rsh32Ux64 x (Const64 <types.Types[types.TUINT64]> [int64(uint16(c))]))
   482  (Rsh32Ux8  x (Const8  [c])) => (Rsh32Ux64 x (Const64 <types.Types[types.TUINT64]> [int64(uint8(c))]))
   483  
   484  (Lsh16x32  x (Const32 [c])) => (Lsh16x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint32(c))]))
   485  (Lsh16x16  x (Const16 [c])) => (Lsh16x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint16(c))]))
   486  (Lsh16x8   x (Const8  [c])) => (Lsh16x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint8(c))]))
   487  (Rsh16x32  x (Const32 [c])) => (Rsh16x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint32(c))]))
   488  (Rsh16x16  x (Const16 [c])) => (Rsh16x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint16(c))]))
   489  (Rsh16x8   x (Const8  [c])) => (Rsh16x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint8(c))]))
   490  (Rsh16Ux32 x (Const32 [c])) => (Rsh16Ux64 x (Const64 <types.Types[types.TUINT64]> [int64(uint32(c))]))
   491  (Rsh16Ux16 x (Const16 [c])) => (Rsh16Ux64 x (Const64 <types.Types[types.TUINT64]> [int64(uint16(c))]))
   492  (Rsh16Ux8  x (Const8  [c])) => (Rsh16Ux64 x (Const64 <types.Types[types.TUINT64]> [int64(uint8(c))]))
   493  
   494  (Lsh8x32  x (Const32 [c])) => (Lsh8x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint32(c))]))
   495  (Lsh8x16  x (Const16 [c])) => (Lsh8x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint16(c))]))
   496  (Lsh8x8   x (Const8  [c])) => (Lsh8x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint8(c))]))
   497  (Rsh8x32  x (Const32 [c])) => (Rsh8x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint32(c))]))
   498  (Rsh8x16  x (Const16 [c])) => (Rsh8x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint16(c))]))
   499  (Rsh8x8   x (Const8  [c])) => (Rsh8x64  x (Const64 <types.Types[types.TUINT64]> [int64(uint8(c))]))
   500  (Rsh8Ux32 x (Const32 [c])) => (Rsh8Ux64 x (Const64 <types.Types[types.TUINT64]> [int64(uint32(c))]))
   501  (Rsh8Ux16 x (Const16 [c])) => (Rsh8Ux64 x (Const64 <types.Types[types.TUINT64]> [int64(uint16(c))]))
   502  (Rsh8Ux8  x (Const8  [c])) => (Rsh8Ux64 x (Const64 <types.Types[types.TUINT64]> [int64(uint8(c))]))
   503  
   504  // shifts by zero
   505  (Lsh(64|32|16|8)x64  x (Const64 [0])) => x
   506  (Rsh(64|32|16|8)x64  x (Const64 [0])) => x
   507  (Rsh(64|32|16|8)Ux64 x (Const64 [0])) => x
   508  
   509  // rotates by multiples of register width
   510  (RotateLeft64 x (Const64 [c])) && c%64 == 0 => x
   511  (RotateLeft32 x (Const32 [c])) && c%32 == 0 => x
   512  (RotateLeft16 x (Const16 [c])) && c%16 == 0 => x
   513  (RotateLeft8  x (Const8 [c]))  && c%8  == 0 => x
   514  
   515  // zero shifted
   516  (Lsh64x(64|32|16|8)  (Const64 [0]) _) => (Const64 [0])
   517  (Rsh64x(64|32|16|8)  (Const64 [0]) _) => (Const64 [0])
   518  (Rsh64Ux(64|32|16|8) (Const64 [0]) _) => (Const64 [0])
   519  (Lsh32x(64|32|16|8)  (Const32 [0]) _) => (Const32 [0])
   520  (Rsh32x(64|32|16|8)  (Const32 [0]) _) => (Const32 [0])
   521  (Rsh32Ux(64|32|16|8) (Const32 [0]) _) => (Const32 [0])
   522  (Lsh16x(64|32|16|8)  (Const16 [0]) _) => (Const16 [0])
   523  (Rsh16x(64|32|16|8)  (Const16 [0]) _) => (Const16 [0])
   524  (Rsh16Ux(64|32|16|8) (Const16 [0]) _) => (Const16 [0])
   525  (Lsh8x(64|32|16|8)   (Const8  [0]) _) => (Const8  [0])
   526  (Rsh8x(64|32|16|8)   (Const8  [0]) _) => (Const8  [0])
   527  (Rsh8Ux(64|32|16|8)  (Const8  [0]) _) => (Const8  [0])
   528  
   529  // large left shifts of all values, and right shifts of unsigned values
   530  ((Lsh64|Rsh64U)x64  _ (Const64 [c])) && uint64(c) >= 64 => (Const64 [0])
   531  ((Lsh32|Rsh32U)x64  _ (Const64 [c])) && uint64(c) >= 32 => (Const32 [0])
   532  ((Lsh16|Rsh16U)x64  _ (Const64 [c])) && uint64(c) >= 16 => (Const16 [0])
   533  ((Lsh8|Rsh8U)x64    _ (Const64 [c])) && uint64(c) >= 8  => (Const8  [0])
   534  
   535  // combine const shifts
   536  (Lsh64x64 <t> (Lsh64x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Lsh64x64 x (Const64 <t> [c+d]))
   537  (Lsh32x64 <t> (Lsh32x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Lsh32x64 x (Const64 <t> [c+d]))
   538  (Lsh16x64 <t> (Lsh16x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Lsh16x64 x (Const64 <t> [c+d]))
   539  (Lsh8x64  <t> (Lsh8x64  x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Lsh8x64  x (Const64 <t> [c+d]))
   540  
   541  (Rsh64x64 <t> (Rsh64x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh64x64 x (Const64 <t> [c+d]))
   542  (Rsh32x64 <t> (Rsh32x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh32x64 x (Const64 <t> [c+d]))
   543  (Rsh16x64 <t> (Rsh16x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh16x64 x (Const64 <t> [c+d]))
   544  (Rsh8x64  <t> (Rsh8x64  x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh8x64  x (Const64 <t> [c+d]))
   545  
   546  (Rsh64Ux64 <t> (Rsh64Ux64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh64Ux64 x (Const64 <t> [c+d]))
   547  (Rsh32Ux64 <t> (Rsh32Ux64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh32Ux64 x (Const64 <t> [c+d]))
   548  (Rsh16Ux64 <t> (Rsh16Ux64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh16Ux64 x (Const64 <t> [c+d]))
   549  (Rsh8Ux64  <t> (Rsh8Ux64  x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh8Ux64  x (Const64 <t> [c+d]))
   550  
   551  // Remove signed right shift before an unsigned right shift that extracts the sign bit.
   552  (Rsh8Ux64  (Rsh8x64  x _) (Const64 <t> [7] )) => (Rsh8Ux64  x (Const64 <t> [7] ))
   553  (Rsh16Ux64 (Rsh16x64 x _) (Const64 <t> [15])) => (Rsh16Ux64 x (Const64 <t> [15]))
   554  (Rsh32Ux64 (Rsh32x64 x _) (Const64 <t> [31])) => (Rsh32Ux64 x (Const64 <t> [31]))
   555  (Rsh64Ux64 (Rsh64x64 x _) (Const64 <t> [63])) => (Rsh64Ux64 x (Const64 <t> [63]))
   556  
   557  // Convert x>>c<<c to x&^(1<<c-1)
   558  (Lsh64x64 i:(Rsh(64|64U)x64  x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 64 && i.Uses == 1 => (And64 x (Const64 <v.Type> [int64(-1) << c]))
   559  (Lsh32x64 i:(Rsh(32|32U)x64  x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 32 && i.Uses == 1 => (And32 x (Const32 <v.Type> [int32(-1) << c]))
   560  (Lsh16x64 i:(Rsh(16|16U)x64  x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 16 && i.Uses == 1 => (And16 x (Const16 <v.Type> [int16(-1) << c]))
   561  (Lsh8x64  i:(Rsh(8|8U)x64    x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 8  && i.Uses == 1 => (And8  x (Const8  <v.Type> [int8(-1)  << c]))
   562  // similarly for x<<c>>c
   563  (Rsh64Ux64 i:(Lsh64x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 64 && i.Uses == 1 => (And64 x (Const64 <v.Type> [int64(^uint64(0)>>c)]))
   564  (Rsh32Ux64 i:(Lsh32x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 32 && i.Uses == 1 => (And32 x (Const32 <v.Type> [int32(^uint32(0)>>c)]))
   565  (Rsh16Ux64 i:(Lsh16x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 16 && i.Uses == 1 => (And16 x (Const16 <v.Type> [int16(^uint16(0)>>c)]))
   566  (Rsh8Ux64  i:(Lsh8x64  x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 8  && i.Uses == 1 => (And8  x (Const8  <v.Type> [int8 (^uint8 (0)>>c)]))
   567  
   568  // ((x >> c1) << c2) >> c3
   569  (Rsh(64|32|16|8)Ux64 (Lsh(64|32|16|8)x64 (Rsh(64|32|16|8)Ux64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
   570    && uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
   571    => (Rsh(64|32|16|8)Ux64 x (Const64 <typ.UInt64> [c1-c2+c3]))
   572  
   573  // ((x << c1) >> c2) << c3
   574  (Lsh(64|32|16|8)x64 (Rsh(64|32|16|8)Ux64 (Lsh(64|32|16|8)x64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
   575    && uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
   576    => (Lsh(64|32|16|8)x64 x (Const64 <typ.UInt64> [c1-c2+c3]))
   577  
   578  // (x >> c) & uppermask = 0
   579  (And64 (Const64 [m]) (Rsh64Ux64 _ (Const64 [c]))) && c >= int64(64-ssa.Ntz64(m)) => (Const64 [0])
   580  (And32 (Const32 [m]) (Rsh32Ux64 _ (Const64 [c]))) && c >= int64(32-ntz32(m)) => (Const32 [0])
   581  (And16 (Const16 [m]) (Rsh16Ux64 _ (Const64 [c]))) && c >= int64(16-ntz16(m)) => (Const16 [0])
   582  (And8  (Const8  [m]) (Rsh8Ux64  _ (Const64 [c]))) && c >= int64(8-ntz8(m))  => (Const8  [0])
   583  
   584  // (x << c) & lowermask = 0
   585  (And64 (Const64 [m]) (Lsh64x64  _ (Const64 [c]))) && c >= int64(64-nlz64(m)) => (Const64 [0])
   586  (And32 (Const32 [m]) (Lsh32x64  _ (Const64 [c]))) && c >= int64(32-nlz32(m)) => (Const32 [0])
   587  (And16 (Const16 [m]) (Lsh16x64  _ (Const64 [c]))) && c >= int64(16-nlz16(m)) => (Const16 [0])
   588  (And8  (Const8  [m]) (Lsh8x64   _ (Const64 [c]))) && c >= int64(8-nlz8(m))  => (Const8  [0])
   589  
   590  // replace shifts with zero extensions
   591  (Rsh16Ux64 (Lsh16x64 x (Const64  [8])) (Const64  [8])) => (ZeroExt8to16  (Trunc16to8  <typ.UInt8>  x))
   592  (Rsh32Ux64 (Lsh32x64 x (Const64 [24])) (Const64 [24])) => (ZeroExt8to32  (Trunc32to8  <typ.UInt8>  x))
   593  (Rsh64Ux64 (Lsh64x64 x (Const64 [56])) (Const64 [56])) => (ZeroExt8to64  (Trunc64to8  <typ.UInt8>  x))
   594  (Rsh32Ux64 (Lsh32x64 x (Const64 [16])) (Const64 [16])) => (ZeroExt16to32 (Trunc32to16 <typ.UInt16> x))
   595  (Rsh64Ux64 (Lsh64x64 x (Const64 [48])) (Const64 [48])) => (ZeroExt16to64 (Trunc64to16 <typ.UInt16> x))
   596  (Rsh64Ux64 (Lsh64x64 x (Const64 [32])) (Const64 [32])) => (ZeroExt32to64 (Trunc64to32 <typ.UInt32> x))
   597  
   598  // replace shifts with sign extensions
   599  (Rsh16x64 (Lsh16x64 x (Const64  [8])) (Const64  [8])) => (SignExt8to16  (Trunc16to8  <typ.Int8>  x))
   600  (Rsh32x64 (Lsh32x64 x (Const64 [24])) (Const64 [24])) => (SignExt8to32  (Trunc32to8  <typ.Int8>  x))
   601  (Rsh64x64 (Lsh64x64 x (Const64 [56])) (Const64 [56])) => (SignExt8to64  (Trunc64to8  <typ.Int8>  x))
   602  (Rsh32x64 (Lsh32x64 x (Const64 [16])) (Const64 [16])) => (SignExt16to32 (Trunc32to16 <typ.Int16> x))
   603  (Rsh64x64 (Lsh64x64 x (Const64 [48])) (Const64 [48])) => (SignExt16to64 (Trunc64to16 <typ.Int16> x))
   604  (Rsh64x64 (Lsh64x64 x (Const64 [32])) (Const64 [32])) => (SignExt32to64 (Trunc64to32 <typ.Int32> x))
   605  
   606  // ((x >> c) & d) << e
   607  (Lsh64x64 (And64 (Rsh(64|64U)x64 <t> x (Const64 <t2> [c])) (Const64 [d])) (Const64 [e])) && c >= e => (And64 (Rsh(64|64U)x64 <t> x (Const64 <t2> [c-e])) (Const64 <t> [d<<e]))
   608  (Lsh32x64 (And32 (Rsh(32|32U)x64 <t> x (Const64 <t2> [c])) (Const32 [d])) (Const64 [e])) && c >= e => (And32 (Rsh(32|32U)x64 <t> x (Const64 <t2> [c-e])) (Const32 <t> [d<<e]))
   609  (Lsh16x64 (And16 (Rsh(16|16U)x64 <t> x (Const64 <t2> [c])) (Const16 [d])) (Const64 [e])) && c >= e => (And16 (Rsh(16|16U)x64 <t> x (Const64 <t2> [c-e])) (Const16 <t> [d<<e]))
   610  (Lsh8x64  (And8  (Rsh(8|8U)x64   <t> x (Const64 <t2> [c])) (Const8  [d])) (Const64 [e])) && c >= e => (And8  (Rsh(8|8U)x64   <t> x (Const64 <t2> [c-e])) (Const8  <t> [d<<e]))
   611  (Lsh64x64 (And64 (Rsh(64|64U)x64 <t> x (Const64 <t2> [c])) (Const64 [d])) (Const64 [e])) && c < e =>  (And64 (Lsh64x64 <t> x (Const64 <t2> [e-c])) (Const64 <t> [d<<e]))
   612  (Lsh32x64 (And32 (Rsh(32|32U)x64 <t> x (Const64 <t2> [c])) (Const32 [d])) (Const64 [e])) && c < e =>  (And32 (Lsh32x64 <t> x (Const64 <t2> [e-c])) (Const32 <t> [d<<e]))
   613  (Lsh16x64 (And16 (Rsh(16|16U)x64 <t> x (Const64 <t2> [c])) (Const16 [d])) (Const64 [e])) && c < e =>  (And16 (Lsh16x64 <t> x (Const64 <t2> [e-c])) (Const16 <t> [d<<e]))
   614  (Lsh8x64  (And8  (Rsh(8|8U)x64   <t> x (Const64 <t2> [c])) (Const8  [d])) (Const64 [e])) && c < e =>  (And8  (Lsh8x64  <t> x (Const64 <t2> [e-c])) (Const8  <t> [d<<e]))
   615  
   616  // constant comparisons
   617  (Eq(64|32|16|8)   (Const(64|32|16|8) [c]) (Const(64|32|16|8) [d])) => (ConstBool [c == d])
   618  (Neq(64|32|16|8)  (Const(64|32|16|8) [c]) (Const(64|32|16|8) [d])) => (ConstBool [c != d])
   619  (Less(64|32|16|8) (Const(64|32|16|8) [c]) (Const(64|32|16|8) [d])) => (ConstBool [c < d])
   620  (Leq(64|32|16|8)  (Const(64|32|16|8) [c]) (Const(64|32|16|8) [d])) => (ConstBool [c <= d])
   621  
   622  (Less64U (Const64 [c]) (Const64 [d])) => (ConstBool [uint64(c) < uint64(d)])
   623  (Less32U (Const32 [c]) (Const32 [d])) => (ConstBool [uint32(c) < uint32(d)])
   624  (Less16U (Const16 [c]) (Const16 [d])) => (ConstBool [uint16(c) < uint16(d)])
   625  (Less8U  (Const8  [c]) (Const8  [d])) => (ConstBool [ uint8(c) <  uint8(d)])
   626  
   627  (Leq64U (Const64 [c]) (Const64 [d])) => (ConstBool [uint64(c) <= uint64(d)])
   628  (Leq32U (Const32 [c]) (Const32 [d])) => (ConstBool [uint32(c) <= uint32(d)])
   629  (Leq16U (Const16 [c]) (Const16 [d])) => (ConstBool [uint16(c) <= uint16(d)])
   630  (Leq8U  (Const8  [c]) (Const8  [d])) => (ConstBool [ uint8(c) <=  uint8(d)])
   631  
   632  (Leq8  (Const8  [0]) (And8  _ (Const8  [c]))) && c >= 0 => (ConstBool [true])
   633  (Leq16 (Const16 [0]) (And16 _ (Const16 [c]))) && c >= 0 => (ConstBool [true])
   634  (Leq32 (Const32 [0]) (And32 _ (Const32 [c]))) && c >= 0 => (ConstBool [true])
   635  (Leq64 (Const64 [0]) (And64 _ (Const64 [c]))) && c >= 0 => (ConstBool [true])
   636  
   637  (Leq8  (Const8  [0]) (Rsh8Ux64  _ (Const64 [c]))) && c > 0 => (ConstBool [true])
   638  (Leq16 (Const16 [0]) (Rsh16Ux64 _ (Const64 [c]))) && c > 0 => (ConstBool [true])
   639  (Leq32 (Const32 [0]) (Rsh32Ux64 _ (Const64 [c]))) && c > 0 => (ConstBool [true])
   640  (Leq64 (Const64 [0]) (Rsh64Ux64 _ (Const64 [c]))) && c > 0 => (ConstBool [true])
   641  
   642  // prefer equalities with zero
   643  (Less(64|32|16|8) (Const(64|32|16|8) <t> [0]) x) && isNonNegative(x) => (Neq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   644  (Less(64|32|16|8)U (Const(64|32|16|8) <t> [0]) x) => (Neq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   645  (Leq(64|32|16|8) x (Const(64|32|16|8) <t> [0])) && isNonNegative(x) => (Eq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   646  (Less(64|32|16|8)U x (Const(64|32|16|8) <t> [1])) => (Eq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   647  (Leq(64|32|16|8)U (Const(64|32|16|8) <t> [1]) x) => (Neq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   648  
   649  // prefer comparisons with zero
   650  (Less(64|32|16|8) x (Const(64|32|16|8) <t> [1])) => (Leq(64|32|16|8) x (Const(64|32|16|8) <t> [0]))
   651  (Leq(64|32|16|8) x (Const(64|32|16|8) <t> [-1])) => (Less(64|32|16|8) x (Const(64|32|16|8) <t> [0]))
   652  (Leq(64|32|16|8) (Const(64|32|16|8) <t> [1]) x) => (Less(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   653  (Less(64|32|16|8) (Const(64|32|16|8) <t> [-1]) x) => (Leq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   654  
   655  // constant floating point comparisons
   656  (Eq32F   (Const32F [c]) (Const32F [d])) => (ConstBool [c == d])
   657  (Eq64F   (Const64F [c]) (Const64F [d])) => (ConstBool [c == d])
   658  (Neq32F  (Const32F [c]) (Const32F [d])) => (ConstBool [c != d])
   659  (Neq64F  (Const64F [c]) (Const64F [d])) => (ConstBool [c != d])
   660  (Less32F (Const32F [c]) (Const32F [d])) => (ConstBool [c < d])
   661  (Less64F (Const64F [c]) (Const64F [d])) => (ConstBool [c < d])
   662  (Leq32F  (Const32F [c]) (Const32F [d])) => (ConstBool [c <= d])
   663  (Leq64F  (Const64F [c]) (Const64F [d])) => (ConstBool [c <= d])
   664  
   665  // simplifications
   666  (Or(64|32|16|8|B) x x) => x
   667  (Or(64|32|16|8) (Const(64|32|16|8)  [0]) x) => x
   668  (Or(64|32|16|8) (Const(64|32|16|8) [-1]) _) => (Const(64|32|16|8) [-1])
   669  (Or(64|32|16|8) (Com(64|32|16|8)     x)  x) => (Const(64|32|16|8) [-1])
   670  (OrB (ConstBool [false]) x) => x
   671  (OrB (ConstBool [true])  _) => (ConstBool [true])
   672  
   673  (And(64|32|16|8|B) x x) => x
   674  (And(64|32|16|8) (Const(64|32|16|8) [-1]) x) => x
   675  (And(64|32|16|8) (Const(64|32|16|8)  [0]) _) => (Const(64|32|16|8) [0])
   676  (And(64|32|16|8) (Com(64|32|16|8)     x)  x) => (Const(64|32|16|8) [0])
   677  (AndB (ConstBool [true])  x) => x
   678  (AndB (ConstBool [false]) _) => (ConstBool [false])
   679  
   680  (Xor(64|32|16|8) x x) => (Const(64|32|16|8) [0])
   681  (Xor(64|32|16|8) (Const(64|32|16|8) [0]) x) => x
   682  (Xor(64|32|16|8) (Com(64|32|16|8)    x)  x) => (Const(64|32|16|8) [-1])
   683  
   684  (Add(64|32|16|8) (Const(64|32|16|8) [0]) x) => x
   685  (Sub(64|32|16|8) x x) => (Const(64|32|16|8) [0])
   686  (Mul(64|32|16|8) (Const(64|32|16|8) [0]) _) => (Const(64|32|16|8) [0])
   687  (Mul(64|32)uover <t> (Const(64|32) [0]) x) => (MakeTuple (Const(64|32) <t.FieldType(0)> [0]) (ConstBool <t.FieldType(1)> [false]))
   688  
   689  (Com(64|32|16|8) (Com(64|32|16|8)  x)) => x
   690  (Com(64|32|16|8) (Const(64|32|16|8) [c])) => (Const(64|32|16|8) [^c])
   691  
   692  (Neg(64|32|16|8) (Sub(64|32|16|8) x y)) => (Sub(64|32|16|8) y x)
   693  (Add(64|32|16|8) x (Neg(64|32|16|8) y)) => (Sub(64|32|16|8) x y)
   694  
   695  (Xor(64|32|16|8) (Const(64|32|16|8) [-1]) x) => (Com(64|32|16|8) x)
   696  
   697  (Sub(64|32|16|8) (Neg(64|32|16|8) x) (Com(64|32|16|8) x)) => (Const(64|32|16|8) [1])
   698  (Sub(64|32|16|8) (Com(64|32|16|8) x) (Neg(64|32|16|8) x)) => (Const(64|32|16|8) [-1])
   699  (Add(64|32|16|8) (Com(64|32|16|8) x)                  x)  => (Const(64|32|16|8) [-1])
   700  
   701  // Prove does not simplify this because x + y might overflow into carry,
   702  // however if no one care about the carry, let it overflow in a normal add.
   703  (Select0 a:(Add64carry x y (Const64 [0]))) && a.Uses == 1 => (Add64 x y)
   704  
   705  // Simplification when involving common integer
   706  // (t + x) - (t + y) == x - y
   707  // (t + x) - (y + t) == x - y
   708  // (x + t) - (y + t) == x - y
   709  // (x + t) - (t + y) == x - y
   710  // (x - t) + (t + y) == x + y
   711  // (x - t) + (y + t) == x + y
   712  (Sub(64|32|16|8) (Add(64|32|16|8) t x) (Add(64|32|16|8) t y)) => (Sub(64|32|16|8) x y)
   713  (Add(64|32|16|8) (Sub(64|32|16|8) x t) (Add(64|32|16|8) t y)) => (Add(64|32|16|8) x y)
   714  
   715  // ^(x-1) == ^x+1 == -x
   716  (Add(64|32|16|8) (Const(64|32|16|8) [1]) (Com(64|32|16|8) x)) => (Neg(64|32|16|8) x)
   717  (Com(64|32|16|8) (Add(64|32|16|8) (Const(64|32|16|8) [-1]) x)) => (Neg(64|32|16|8) x)
   718  
   719  // -(-x) == x
   720  (Neg(64|32|16|8) (Neg(64|32|16|8) x)) => x
   721  
   722  // -^x == x+1
   723  (Neg(64|32|16|8) <t> (Com(64|32|16|8) x)) => (Add(64|32|16|8) (Const(64|32|16|8) <t> [1]) x)
   724  
   725  (And(64|32|16|8) x (And(64|32|16|8) x y)) => (And(64|32|16|8) x y)
   726  (Or(64|32|16|8) x (Or(64|32|16|8) x y)) => (Or(64|32|16|8) x y)
   727  (Xor(64|32|16|8) x (Xor(64|32|16|8) x y)) => y
   728  
   729  // x-(x&y) == x&^y
   730  (Sub(64|32|16|8) x (And(64|32|16|8) <t> x y)) => (And(64|32|16|8) x (Com(64|32|16|8) <t> y))
   731  
   732  // Fold comparisons with numeric bounds
   733  (Less(64|32|16|8)U _ (Const(64|32|16|8) [0]))  => (ConstBool [false])
   734  (Leq(64|32|16|8)U (Const(64|32|16|8) [0]) _)   => (ConstBool [true])
   735  (Less(64|32|16|8)U (Const(64|32|16|8) [-1]) _) => (ConstBool [false])
   736  (Leq(64|32|16|8)U _ (Const(64|32|16|8) [-1]))  => (ConstBool [true])
   737  (Less64 _ (Const64 [math.MinInt64])) => (ConstBool [false])
   738  (Less32 _ (Const32 [math.MinInt32])) => (ConstBool [false])
   739  (Less16 _ (Const16 [math.MinInt16])) => (ConstBool [false])
   740  (Less8  _ (Const8  [math.MinInt8 ])) => (ConstBool [false])
   741  (Leq64 (Const64 [math.MinInt64]) _)  => (ConstBool [true])
   742  (Leq32 (Const32 [math.MinInt32]) _)  => (ConstBool [true])
   743  (Leq16 (Const16 [math.MinInt16]) _)  => (ConstBool [true])
   744  (Leq8  (Const8  [math.MinInt8 ]) _)  => (ConstBool [true])
   745  (Less64 (Const64 [math.MaxInt64]) _) => (ConstBool [false])
   746  (Less32 (Const32 [math.MaxInt32]) _) => (ConstBool [false])
   747  (Less16 (Const16 [math.MaxInt16]) _) => (ConstBool [false])
   748  (Less8  (Const8  [math.MaxInt8 ]) _) => (ConstBool [false])
   749  (Leq64 _ (Const64 [math.MaxInt64]))  => (ConstBool [true])
   750  (Leq32 _ (Const32 [math.MaxInt32]))  => (ConstBool [true])
   751  (Leq16 _ (Const16 [math.MaxInt16]))  => (ConstBool [true])
   752  (Leq8  _ (Const8  [math.MaxInt8 ]))  => (ConstBool [true])
   753  
   754  // Canonicalize <= on numeric bounds and < near numeric bounds to ==
   755  (Leq(64|32|16|8)U x c:(Const(64|32|16|8) [0]))     => (Eq(64|32|16|8) x c)
   756  (Leq(64|32|16|8)U c:(Const(64|32|16|8) [-1]) x)    => (Eq(64|32|16|8) x c)
   757  (Less(64|32|16|8)U x (Const(64|32|16|8) <t> [1]))  => (Eq(64|32|16|8) x (Const(64|32|16|8) <t> [0]))
   758  (Less(64|32|16|8)U (Const(64|32|16|8) <t> [-2]) x) => (Eq(64|32|16|8) x (Const(64|32|16|8) <t> [-1]))
   759  (Leq64 x c:(Const64 [math.MinInt64])) => (Eq64 x c)
   760  (Leq32 x c:(Const32 [math.MinInt32])) => (Eq32 x c)
   761  (Leq16 x c:(Const16 [math.MinInt16])) => (Eq16 x c)
   762  (Leq8  x c:(Const8  [math.MinInt8 ])) => (Eq8  x c)
   763  (Leq64 c:(Const64 [math.MaxInt64]) x) => (Eq64 x c)
   764  (Leq32 c:(Const32 [math.MaxInt32]) x) => (Eq32 x c)
   765  (Leq16 c:(Const16 [math.MaxInt16]) x) => (Eq16 x c)
   766  (Leq8  c:(Const8  [math.MaxInt8 ]) x) => (Eq8  x c)
   767  (Less64 x (Const64 <t> [math.MinInt64+1])) => (Eq64 x (Const64 <t> [math.MinInt64]))
   768  (Less32 x (Const32 <t> [math.MinInt32+1])) => (Eq32 x (Const32 <t> [math.MinInt32]))
   769  (Less16 x (Const16 <t> [math.MinInt16+1])) => (Eq16 x (Const16 <t> [math.MinInt16]))
   770  (Less8  x (Const8  <t> [math.MinInt8 +1])) => (Eq8  x (Const8  <t> [math.MinInt8 ]))
   771  (Less64 (Const64 <t> [math.MaxInt64-1]) x) => (Eq64 x (Const64 <t> [math.MaxInt64]))
   772  (Less32 (Const32 <t> [math.MaxInt32-1]) x) => (Eq32 x (Const32 <t> [math.MaxInt32]))
   773  (Less16 (Const16 <t> [math.MaxInt16-1]) x) => (Eq16 x (Const16 <t> [math.MaxInt16]))
   774  (Less8  (Const8  <t> [math.MaxInt8 -1]) x) => (Eq8  x (Const8  <t> [math.MaxInt8 ]))
   775  
   776  // Ands clear bits. Ors set bits.
   777  // If a subsequent Or will set all the bits
   778  // that an And cleared, we can skip the And.
   779  // This happens in bitmasking code like:
   780  //   x &^= 3 << shift // clear two old bits
   781  //   x  |= v << shift // set two new bits
   782  // when shift is a small constant and v ends up a constant 3.
   783  (Or8  (And8  x (Const8  [c2])) (Const8  <t> [c1])) && ^(c1 | c2) == 0 => (Or8  (Const8  <t> [c1]) x)
   784  (Or16 (And16 x (Const16 [c2])) (Const16 <t> [c1])) && ^(c1 | c2) == 0 => (Or16 (Const16 <t> [c1]) x)
   785  (Or32 (And32 x (Const32 [c2])) (Const32 <t> [c1])) && ^(c1 | c2) == 0 => (Or32 (Const32 <t> [c1]) x)
   786  (Or64 (And64 x (Const64 [c2])) (Const64 <t> [c1])) && ^(c1 | c2) == 0 => (Or64 (Const64 <t> [c1]) x)
   787  
   788  (Trunc64to8  (And64 (Const64 [y]) x)) && y&0xFF == 0xFF => (Trunc64to8 x)
   789  (Trunc64to16 (And64 (Const64 [y]) x)) && y&0xFFFF == 0xFFFF => (Trunc64to16 x)
   790  (Trunc64to32 (And64 (Const64 [y]) x)) && y&0xFFFFFFFF == 0xFFFFFFFF => (Trunc64to32 x)
   791  (Trunc32to8  (And32 (Const32 [y]) x)) && y&0xFF == 0xFF => (Trunc32to8 x)
   792  (Trunc32to16 (And32 (Const32 [y]) x)) && y&0xFFFF == 0xFFFF => (Trunc32to16 x)
   793  (Trunc16to8  (And16 (Const16 [y]) x)) && y&0xFF == 0xFF => (Trunc16to8 x)
   794  
   795  (ZeroExt8to64  (Trunc64to8  x:(Rsh64Ux64 _ (Const64 [s])))) && s >= 56 => x
   796  (ZeroExt16to64 (Trunc64to16 x:(Rsh64Ux64 _ (Const64 [s])))) && s >= 48 => x
   797  (ZeroExt32to64 (Trunc64to32 x:(Rsh64Ux64 _ (Const64 [s])))) && s >= 32 => x
   798  (ZeroExt8to32  (Trunc32to8  x:(Rsh32Ux64 _ (Const64 [s])))) && s >= 24 => x
   799  (ZeroExt16to32 (Trunc32to16 x:(Rsh32Ux64 _ (Const64 [s])))) && s >= 16 => x
   800  (ZeroExt8to16  (Trunc16to8  x:(Rsh16Ux64 _ (Const64 [s])))) && s >= 8 => x
   801  
   802  (SignExt8to64  (Trunc64to8  x:(Rsh64x64 _ (Const64 [s])))) && s >= 56 => x
   803  (SignExt16to64 (Trunc64to16 x:(Rsh64x64 _ (Const64 [s])))) && s >= 48 => x
   804  (SignExt32to64 (Trunc64to32 x:(Rsh64x64 _ (Const64 [s])))) && s >= 32 => x
   805  (SignExt8to32  (Trunc32to8  x:(Rsh32x64 _ (Const64 [s])))) && s >= 24 => x
   806  (SignExt16to32 (Trunc32to16 x:(Rsh32x64 _ (Const64 [s])))) && s >= 16 => x
   807  (SignExt8to16  (Trunc16to8  x:(Rsh16x64 _ (Const64 [s])))) && s >= 8 => x
   808  
   809  (Slicemask (Const32 [x])) && x > 0 => (Const32 [-1])
   810  (Slicemask (Const32 [0]))          => (Const32 [0])
   811  (Slicemask (Const64 [x])) && x > 0 => (Const64 [-1])
   812  (Slicemask (Const64 [0]))          => (Const64 [0])
   813  
   814  // simplifications often used for lengths.  e.g. len(s[i:i+5])==5
   815  (Sub(64|32|16|8) (Add(64|32|16|8) x y) x) => y
   816  (Sub(64|32|16|8) (Add(64|32|16|8) x y) y) => x
   817  (Sub(64|32|16|8) (Sub(64|32|16|8) x y) x) => (Neg(64|32|16|8) y)
   818  (Sub(64|32|16|8) x (Add(64|32|16|8) x y)) => (Neg(64|32|16|8) y)
   819  (Add(64|32|16|8) x (Sub(64|32|16|8) y x)) => y
   820  (Add(64|32|16|8) x (Add(64|32|16|8) y (Sub(64|32|16|8) z x))) => (Add(64|32|16|8) y z)
   821  // x + (y - (x - z)) == y + z
   822  (Add(64|32|16|8) x (Sub(64|32|16|8) y (Sub(64|32|16|8) x z))) => (Add(64|32|16|8) y z)
   823  
   824  // basic phi simplifications
   825  (Phi (Const8  [c]) (Const8  [c])) => (Const8  [c])
   826  (Phi (Const16 [c]) (Const16 [c])) => (Const16 [c])
   827  (Phi (Const32 [c]) (Const32 [c])) => (Const32 [c])
   828  (Phi (Const64 [c]) (Const64 [c])) => (Const64 [c])
   829  
   830  // slice and interface comparisons
   831  // The frontend ensures that we can only compare against nil,
   832  // so we need only compare the first word (interface type or slice ptr).
   833  (EqInter x y)  => (EqPtr  (ITab x) (ITab y))
   834  (NeqInter x y) => (NeqPtr (ITab x) (ITab y))
   835  (EqSlice x y)  => (EqPtr  (SlicePtr x) (SlicePtr y))
   836  (NeqSlice x y) => (NeqPtr (SlicePtr x) (SlicePtr y))
   837  
   838  // Load of store of same address, with compatibly typed value and same size
   839  (Load <t1> p1 (Store {t2} p2 x _))
   840  	&& ssa.IsSamePtr(p1, p2)
   841  	&& copyCompatibleType(t1, x.Type)
   842  	&& t1.Size() == t2.Size()
   843  	=> x
   844  (Load <t1> p1 (Store {t2} p2 _ (Store {t3} p3 x _)))
   845  	&& ssa.IsSamePtr(p1, p3)
   846  	&& copyCompatibleType(t1, x.Type)
   847  	&& t1.Size() == t3.Size()
   848  	&& ssa.Disjoint(p3, t3, p2, t2)
   849  	=> x
   850  (Load <t1> p1 (Store {t2} p2 _ (Store {t3} p3 _ (Store {t4} p4 x _))))
   851  	&& ssa.IsSamePtr(p1, p4)
   852  	&& copyCompatibleType(t1, x.Type)
   853  	&& t1.Size() == t4.Size()
   854  	&& ssa.Disjoint(p4, t4, p2, t2)
   855  	&& ssa.Disjoint(p4, t4, p3, t3)
   856  	=> x
   857  (Load <t1> p1 (Store {t2} p2 _ (Store {t3} p3 _ (Store {t4} p4 _ (Store {t5} p5 x _)))))
   858  	&& ssa.IsSamePtr(p1, p5)
   859  	&& copyCompatibleType(t1, x.Type)
   860  	&& t1.Size() == t5.Size()
   861  	&& ssa.Disjoint(p5, t5, p2, t2)
   862  	&& ssa.Disjoint(p5, t5, p3, t3)
   863  	&& ssa.Disjoint(p5, t5, p4, t4)
   864  	=> x
   865  
   866  // Load from a region just copied by Move can read directly from the source.
   867  (Load <t1> op1:(OffPtr [o1] p1) move:(Move [n] p2 src mem))
   868  	&& o1 >= 0 && o1+t1.Size() <= n && ssa.IsSamePtr(p1, p2)
   869  	&& !ssa.IsVolatile(src)
   870  	=> @move.Block (Load <t1> (OffPtr <op1.Type> [o1] src) mem)
   871  
   872  // Pass constants through math.Float{32,64}bits and math.Float{32,64}frombits
   873  (Load <t1> p1 (Store {t2} p2 (Const64  [x]) _)) && ssa.IsSamePtr(p1,p2) && t2.Size() == 8 && ssa.Is64BitFloat(t1) && !math.IsNaN(math.Float64frombits(uint64(x))) => (Const64F [math.Float64frombits(uint64(x))])
   874  (Load <t1> p1 (Store {t2} p2 (Const32  [x]) _)) && ssa.IsSamePtr(p1,p2) && t2.Size() == 4 && ssa.Is32BitFloat(t1) && !math.IsNaN(float64(math.Float32frombits(uint32(x)))) => (Const32F [math.Float32frombits(uint32(x))])
   875  (Load <t1> p1 (Store {t2} p2 (Const64F [x]) _)) && ssa.IsSamePtr(p1,p2) && t2.Size() == 8 && ssa.Is64BitInt(t1)   => (Const64  [int64(math.Float64bits(x))])
   876  (Load <t1> p1 (Store {t2} p2 (Const32F [x]) _)) && ssa.IsSamePtr(p1,p2) && t2.Size() == 4 && ssa.Is32BitInt(t1)   => (Const32  [int32(math.Float32bits(x))])
   877  
   878  // Float Loads up to Zeros so they can be constant folded.
   879  (Load <t1> op1:(OffPtr [o1] p1)
   880  	(Store {t2} p2 _
   881  		mem:(Zero [n] p3 _)))
   882  	&& o1 >= 0 && o1+t1.Size() <= n && ssa.IsSamePtr(p1, p3)
   883  	&& ssa.CanSSA(t1)
   884  	&& ssa.Disjoint(op1, t1, p2, t2)
   885  	=> @mem.Block (Load <t1> (OffPtr <op1.Type> [o1] p3) mem)
   886  (Load <t1> op1:(OffPtr [o1] p1)
   887  	(Store {t2} p2 _
   888  		(Store {t3} p3 _
   889  			mem:(Zero [n] p4 _))))
   890  	&& o1 >= 0 && o1+t1.Size() <= n && ssa.IsSamePtr(p1, p4)
   891  	&& ssa.CanSSA(t1)
   892  	&& ssa.Disjoint(op1, t1, p2, t2)
   893  	&& ssa.Disjoint(op1, t1, p3, t3)
   894  	=> @mem.Block (Load <t1> (OffPtr <op1.Type> [o1] p4) mem)
   895  (Load <t1> op1:(OffPtr [o1] p1)
   896  	(Store {t2} p2 _
   897  		(Store {t3} p3 _
   898  			(Store {t4} p4 _
   899  				mem:(Zero [n] p5 _)))))
   900  	&& o1 >= 0 && o1+t1.Size() <= n && ssa.IsSamePtr(p1, p5)
   901  	&& ssa.CanSSA(t1)
   902  	&& ssa.Disjoint(op1, t1, p2, t2)
   903  	&& ssa.Disjoint(op1, t1, p3, t3)
   904  	&& ssa.Disjoint(op1, t1, p4, t4)
   905  	=> @mem.Block (Load <t1> (OffPtr <op1.Type> [o1] p5) mem)
   906  (Load <t1> op1:(OffPtr [o1] p1)
   907  	(Store {t2} p2 _
   908  		(Store {t3} p3 _
   909  			(Store {t4} p4 _
   910  				(Store {t5} p5 _
   911  					mem:(Zero [n] p6 _))))))
   912  	&& o1 >= 0 && o1+t1.Size() <= n && ssa.IsSamePtr(p1, p6)
   913  	&& ssa.CanSSA(t1)
   914  	&& ssa.Disjoint(op1, t1, p2, t2)
   915  	&& ssa.Disjoint(op1, t1, p3, t3)
   916  	&& ssa.Disjoint(op1, t1, p4, t4)
   917  	&& ssa.Disjoint(op1, t1, p5, t5)
   918  	=> @mem.Block (Load <t1> (OffPtr <op1.Type> [o1] p6) mem)
   919  
   920  // Zero to Load forwarding.
   921  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   922  	&& t1.IsBoolean()
   923  	&& ssa.IsSamePtr(p1, p2)
   924  	&& n >= o + 1
   925  	=> (ConstBool [false])
   926  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   927  	&& ssa.Is8BitInt(t1)
   928  	&& ssa.IsSamePtr(p1, p2)
   929  	&& n >= o + 1
   930  	=> (Const8 [0])
   931  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   932  	&& ssa.Is16BitInt(t1)
   933  	&& ssa.IsSamePtr(p1, p2)
   934  	&& n >= o + 2
   935  	=> (Const16 [0])
   936  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   937  	&& ssa.Is32BitInt(t1)
   938  	&& ssa.IsSamePtr(p1, p2)
   939  	&& n >= o + 4
   940  	=> (Const32 [0])
   941  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   942  	&& ssa.Is64BitInt(t1)
   943  	&& ssa.IsSamePtr(p1, p2)
   944  	&& n >= o + 8
   945  	=> (Const64 [0])
   946  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   947  	&& ssa.Is32BitFloat(t1)
   948  	&& ssa.IsSamePtr(p1, p2)
   949  	&& n >= o + 4
   950  	=> (Const32F [0])
   951  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   952  	&& ssa.Is64BitFloat(t1)
   953  	&& ssa.IsSamePtr(p1, p2)
   954  	&& n >= o + 8
   955  	=> (Const64F [0])
   956  
   957  // Eliminate stores of values that have just been loaded from the same location.
   958  // We also handle the common case where there are some intermediate stores.
   959  (Store {t1} p1 (Load <t2> p2 mem) mem)
   960  	&& ssa.IsSamePtr(p1, p2)
   961  	&& t2.Size() == t1.Size()
   962  	=> mem
   963  (Store {t1} p1 (Load <t2> p2 oldmem) mem:(Store {t3} p3 _ oldmem))
   964  	&& ssa.IsSamePtr(p1, p2)
   965  	&& t2.Size() == t1.Size()
   966  	&& ssa.Disjoint(p1, t1, p3, t3)
   967  	=> mem
   968  (Store {t1} p1 (Load <t2> p2 oldmem) mem:(Store {t3} p3 _ (Store {t4} p4 _ oldmem)))
   969  	&& ssa.IsSamePtr(p1, p2)
   970  	&& t2.Size() == t1.Size()
   971  	&& ssa.Disjoint(p1, t1, p3, t3)
   972  	&& ssa.Disjoint(p1, t1, p4, t4)
   973  	=> mem
   974  (Store {t1} p1 (Load <t2> p2 oldmem) mem:(Store {t3} p3 _ (Store {t4} p4 _ (Store {t5} p5 _ oldmem))))
   975  	&& ssa.IsSamePtr(p1, p2)
   976  	&& t2.Size() == t1.Size()
   977  	&& ssa.Disjoint(p1, t1, p3, t3)
   978  	&& ssa.Disjoint(p1, t1, p4, t4)
   979  	&& ssa.Disjoint(p1, t1, p5, t5)
   980  	=> mem
   981  
   982  // Don't Store zeros to cleared variables.
   983  (Store {t} (OffPtr [o] p1) x mem:(Zero [n] p2 _))
   984  	&& ssa.IsConstZero(x)
   985  	&& o >= 0 && t.Size() + o <= n && ssa.IsSamePtr(p1, p2)
   986  	=> mem
   987  (Store {t1} op1:(OffPtr [o1] p1) x mem:(Store {t2} p2 _ (Zero [n] p3 _)))
   988  	&& ssa.IsConstZero(x)
   989  	&& o1 >= 0 && t1.Size() + o1 <= n && ssa.IsSamePtr(p1, p3)
   990  	&& ssa.Disjoint(op1, t1, p2, t2)
   991  	=> mem
   992  (Store {t1} op1:(OffPtr [o1] p1) x mem:(Store {t2} p2 _ (Store {t3} p3 _ (Zero [n] p4 _))))
   993  	&& ssa.IsConstZero(x)
   994  	&& o1 >= 0 && t1.Size() + o1 <= n && ssa.IsSamePtr(p1, p4)
   995  	&& ssa.Disjoint(op1, t1, p2, t2)
   996  	&& ssa.Disjoint(op1, t1, p3, t3)
   997  	=> mem
   998  (Store {t1} op1:(OffPtr [o1] p1) x mem:(Store {t2} p2 _ (Store {t3} p3 _ (Store {t4} p4 _ (Zero [n] p5 _)))))
   999  	&& ssa.IsConstZero(x)
  1000  	&& o1 >= 0 && t1.Size() + o1 <= n && ssa.IsSamePtr(p1, p5)
  1001  	&& ssa.Disjoint(op1, t1, p2, t2)
  1002  	&& ssa.Disjoint(op1, t1, p3, t3)
  1003  	&& ssa.Disjoint(op1, t1, p4, t4)
  1004  	=> mem
  1005  
  1006  // Collapse OffPtr
  1007  (OffPtr (OffPtr p [y]) [x]) => (OffPtr p [x+y])
  1008  (OffPtr p [0]) && v.Type.Compare(p.Type) == types.CMPeq => p
  1009  
  1010  // indexing operations
  1011  // Note: bounds check has already been done
  1012  (PtrIndex <t> ptr idx) && config.PtrSize == 4 && ssa.Is32Bit(t.Elem().Size()) => (AddPtr ptr (Mul32 <typ.Int> idx (Const32 <typ.Int> [int32(t.Elem().Size())])))
  1013  (PtrIndex <t> ptr idx) && config.PtrSize == 8 => (AddPtr ptr (Mul64 <typ.Int> idx (Const64 <typ.Int> [t.Elem().Size()])))
  1014  
  1015  // struct operations
  1016  (StructSelect [i] x:(StructMake ___)) => x.Args[i]
  1017  (Load <t> _ _) && t.IsStruct() && t.Size() > 0 && ssa.CanSSA(t) && !t.IsSIMD() => rewriteStructLoad(v)
  1018  (Store _ (StructMake ___) _) => ssa.RewriteStructStore(v)
  1019  
  1020  (StructSelect [i] x:(Load <t> ptr mem)) && !ssa.CanSSA(t) =>
  1021    @x.Block (Load <v.Type> (OffPtr <v.Type.PtrTo()> [t.FieldOff(int(i))] ptr) mem)
  1022  
  1023  // Putting struct{*byte} and similar into direct interfaces.
  1024  (IMake _typ (StructMake ___)) => ssa.ImakeOfStructMake(v)
  1025  (StructSelect (IData x)) && v.Type.Size() > 0 => (IData x)
  1026  (StructSelect (IData x)) && v.Type.Size() == 0 => (Empty)
  1027  
  1028  // un-SSAable values use mem->mem copies
  1029  (Store {t} dst (Load src mem) mem) && !ssa.CanSSA(t) =>
  1030  	(Move {t} [t.Size()] dst src mem)
  1031  (Store {t} dst (Load src mem) (VarDef {x} mem)) && !ssa.CanSSA(t) =>
  1032  	(Move {t} [t.Size()] dst src (VarDef {x} mem))
  1033  
  1034  // array ops
  1035  (ArraySelect (ArrayMake1 x)) => x
  1036  
  1037  (Load <t> ptr mem) && t.IsArray() && t.NumElem() == 1 && t.Size() > 0 && ssa.CanSSA(t) =>
  1038    (ArrayMake1 (Load <t.Elem()> ptr mem))
  1039  
  1040  (Store dst (ArrayMake1 e) mem) => (Store {e.Type} dst e mem)
  1041  
  1042  // Putting [1]*byte and similar into direct interfaces.
  1043  (IMake _typ (ArrayMake1 val)) => (IMake _typ val)
  1044  (ArraySelect [0] (IData x)) => (IData x)
  1045  
  1046  // zero-sized values.
  1047  (Load <t> _ _) && t.Size() == 0 => (Empty)
  1048  (Store _ (Empty) mem) => mem
  1049  
  1050  // string ops
  1051  // Decomposing StringMake and lowering of StringPtr and StringLen
  1052  // happens in a later pass, dec, so that these operations are available
  1053  // to other passes for optimizations.
  1054  (StringPtr (StringMake (Addr <t> {s} base) _)) => (Addr <t> {s} base)
  1055  (StringLen (StringMake _ (Const64 <t> [c]))) => (Const64 <t> [c])
  1056  (ConstString {str}) && config.PtrSize == 4 && str == "" =>
  1057    (StringMake (ConstNil) (Const32 <typ.Int> [0]))
  1058  (ConstString {str}) && config.PtrSize == 8 && str == "" =>
  1059    (StringMake (ConstNil) (Const64 <typ.Int> [0]))
  1060  (ConstString {str}) && config.PtrSize == 4 && str != "" =>
  1061    (StringMake
  1062      (Addr <typ.BytePtr> {fe.StringData(str)}
  1063        (SB))
  1064      (Const32 <typ.Int> [int32(len(str))]))
  1065  (ConstString {str}) && config.PtrSize == 8 && str != "" =>
  1066    (StringMake
  1067      (Addr <typ.BytePtr> {fe.StringData(str)}
  1068        (SB))
  1069      (Const64 <typ.Int> [int64(len(str))]))
  1070  
  1071  // slice ops
  1072  // Only a few slice rules are provided here.  See dec.rules for
  1073  // a more comprehensive set.
  1074  (SliceLen (SliceMake _ (Const64 <t> [c]) _)) => (Const64 <t> [c])
  1075  (SliceCap (SliceMake _ _ (Const64 <t> [c]))) => (Const64 <t> [c])
  1076  (SliceLen (SliceMake _ (Const32 <t> [c]) _)) => (Const32 <t> [c])
  1077  (SliceCap (SliceMake _ _ (Const32 <t> [c]))) => (Const32 <t> [c])
  1078  (SlicePtr (SliceMake (SlicePtr x) _ _)) => (SlicePtr x)
  1079  (SliceLen (SliceMake _ (SliceLen x) _)) => (SliceLen x)
  1080  (SliceCap (SliceMake _ _ (SliceCap x))) => (SliceCap x)
  1081  (SliceCap (SliceMake _ _ (SliceLen x))) => (SliceLen x)
  1082  (ConstSlice) && config.PtrSize == 4 =>
  1083    (SliceMake
  1084      (ConstNil <v.Type.Elem().PtrTo()>)
  1085      (Const32 <typ.Int> [0])
  1086      (Const32 <typ.Int> [0]))
  1087  (ConstSlice) && config.PtrSize == 8 =>
  1088    (SliceMake
  1089      (ConstNil <v.Type.Elem().PtrTo()>)
  1090      (Const64 <typ.Int> [0])
  1091      (Const64 <typ.Int> [0]))
  1092  (SliceLen (Phi (SliceMake _ x _) (SliceMake _ x _))) => x
  1093  (SliceCap (Phi (SliceMake _ _ x) (SliceMake _ _ x))) => x
  1094  
  1095  // Special rule to help constant slicing; len > 0 implies cap > 0 implies Slicemask is all 1
  1096  (SliceMake (AddPtr <t> x (And64 y (Slicemask _))) w:(Const64 [c]) z) && c > 0 => (SliceMake (AddPtr <t> x y) w z)
  1097  (SliceMake (AddPtr <t> x (And32 y (Slicemask _))) w:(Const32 [c]) z) && c > 0 => (SliceMake (AddPtr <t> x y) w z)
  1098  
  1099  // interface ops
  1100  (ConstInterface) =>
  1101    (IMake
  1102      (ConstNil <typ.Uintptr>)
  1103      (ConstNil <typ.BytePtr>))
  1104  
  1105  (NilCheck ptr:(GetG mem) mem) => ptr
  1106  
  1107  (If (Not cond) yes no) => (If cond no yes)
  1108  (If (ConstBool [c]) yes no) && c => (First yes no)
  1109  (If (ConstBool [c]) yes no) && !c => (First no yes)
  1110  
  1111  (Phi <t> nx:(Not x) ny:(Not y)) && nx.Uses == 1 && ny.Uses == 1 => (Not (Phi <t> x y))
  1112  
  1113  // Get rid of Convert ops for pointer arithmetic on unsafe.Pointer.
  1114  (Convert (Add(64|32) (Convert ptr mem) off) mem) => (AddPtr ptr off)
  1115  (Convert (Convert ptr mem) mem) => ptr
  1116  // Note: it is important that the target rewrite is ptr+(off1+off2), not (ptr+off1)+off2.
  1117  // We must ensure that no intermediate computations are invalid pointers.
  1118  (Convert a:(Add(64|32) (Add(64|32) (Convert ptr mem) off1) off2) mem) => (AddPtr ptr (Add(64|32) <a.Type> off1 off2))
  1119  
  1120  // Simplification of divisions.
  1121  // Only trivial, easily analyzed (by prove) rewrites here.
  1122  // Strength reduction of div to mul is delayed to divmod.rules.
  1123  
  1124  // Signed divide by a negative constant.  Rewrite to divide by a positive constant.
  1125  (Div8  <t> n (Const8  [c])) && c < 0 && c != -1<<7  => (Neg8  (Div8  <t> n (Const8  <t> [-c])))
  1126  (Div16 <t> n (Const16 [c])) && c < 0 && c != -1<<15 => (Neg16 (Div16 <t> n (Const16 <t> [-c])))
  1127  (Div32 <t> n (Const32 [c])) && c < 0 && c != -1<<31 => (Neg32 (Div32 <t> n (Const32 <t> [-c])))
  1128  (Div64 <t> n (Const64 [c])) && c < 0 && c != -1<<63 => (Neg64 (Div64 <t> n (Const64 <t> [-c])))
  1129  
  1130  // Dividing by the most-negative number.  Result is always 0 except
  1131  // if the input is also the most-negative number.
  1132  // We can detect that using the sign bit of x & -x.
  1133  (Div64 x (Const64 [-1<<63])) && isNonNegative(x) => (Const64 [0])
  1134  (Div8  <t> x (Const8  [-1<<7 ])) => (Rsh8Ux64  (And8  <t> x (Neg8  <t> x)) (Const64 <typ.UInt64> [7 ]))
  1135  (Div16 <t> x (Const16 [-1<<15])) => (Rsh16Ux64 (And16 <t> x (Neg16 <t> x)) (Const64 <typ.UInt64> [15]))
  1136  (Div32 <t> x (Const32 [-1<<31])) => (Rsh32Ux64 (And32 <t> x (Neg32 <t> x)) (Const64 <typ.UInt64> [31]))
  1137  (Div64 <t> x (Const64 [-1<<63])) => (Rsh64Ux64 (And64 <t> x (Neg64 <t> x)) (Const64 <typ.UInt64> [63]))
  1138  
  1139  // Unsigned divide by power of 2.  Strength reduce to a shift.
  1140  (Div8u  n (Const8  [c])) && ssa.IsPowerOfTwo(uint8(c)) => (Rsh8Ux64  n (Const64 <typ.UInt64> [ssa.Log8u(uint8(c))]))
  1141  (Div16u n (Const16 [c])) && ssa.IsPowerOfTwo(uint16(c)) => (Rsh16Ux64 n (Const64 <typ.UInt64> [ssa.Log16u(uint16(c))]))
  1142  (Div32u n (Const32 [c])) && ssa.IsPowerOfTwo(uint32(c)) => (Rsh32Ux64 n (Const64 <typ.UInt64> [ssa.Log32u(uint32(c))]))
  1143  (Div64u n (Const64 [c])) && ssa.IsPowerOfTwo(uint64(c)) => (Rsh64Ux64 n (Const64 <typ.UInt64> [ssa.Log64u(uint64(c))]))
  1144  
  1145  // Strength reduce multiplication by a power of two to a shift.
  1146  // Excluded from early opt so that prove can recognize mod
  1147  // by the x - (x/d)*d pattern.
  1148  // (Runs during "middle opt" and "late opt".)
  1149  (Mul8  <t> x (Const8  [c])) && ssa.IsPowerOfTwo(uint8(c)) && v.Block.Func.Pass.Name != "opt" =>
  1150    (Lsh8x64  <t> x (Const64 <typ.UInt64> [ssa.Log8u(uint8(c))]))
  1151  (Mul16 <t> x (Const16 [c])) && ssa.IsPowerOfTwo(uint16(c)) && v.Block.Func.Pass.Name != "opt" =>
  1152    (Lsh16x64 <t> x (Const64 <typ.UInt64> [ssa.Log16u(uint16(c))]))
  1153  (Mul32 <t> x (Const32 [c])) && ssa.IsPowerOfTwo(uint32(c)) && v.Block.Func.Pass.Name != "opt" =>
  1154    (Lsh32x64 <t> x (Const64 <typ.UInt64> [ssa.Log32u(uint32(c))]))
  1155  (Mul64 <t> x (Const64 [c])) && ssa.IsPowerOfTwo(uint64(c)) && v.Block.Func.Pass.Name != "opt" =>
  1156    (Lsh64x64 <t> x (Const64 <typ.UInt64> [ssa.Log64u(uint64(c))]))
  1157  (Mul8  <t> x (Const8  [c])) && ssa.IsPowerOfTwo(uint8(-c)) && v.Block.Func.Pass.Name != "opt" =>
  1158    (Neg8  (Lsh8x64  <t> x (Const64 <typ.UInt64> [ssa.Log8u(uint8(-c))])))
  1159  (Mul16 <t> x (Const16 [c])) && ssa.IsPowerOfTwo(uint16(-c)) && v.Block.Func.Pass.Name != "opt" =>
  1160    (Neg16 (Lsh16x64 <t> x (Const64 <typ.UInt64> [ssa.Log16u(uint16(-c))])))
  1161  (Mul32 <t> x (Const32 [c])) && ssa.IsPowerOfTwo(uint32(-c)) && v.Block.Func.Pass.Name != "opt" =>
  1162    (Neg32 (Lsh32x64 <t> x (Const64 <typ.UInt64> [ssa.Log32u(uint32(-c))])))
  1163  (Mul64 <t> x (Const64 [c])) && ssa.IsPowerOfTwo(uint64(-c)) && v.Block.Func.Pass.Name != "opt" =>
  1164    (Neg64 (Lsh64x64 <t> x (Const64 <typ.UInt64> [ssa.Log64u(uint64(-c))])))
  1165  
  1166  // Strength reduction of mod to div.
  1167  // Strength reduction of div to mul is delayed to divmod.rules.
  1168  
  1169  // Unsigned mod by power of 2 constant.
  1170  (Mod8u  <t> n (Const8  [c])) && ssa.IsPowerOfTwo(uint8(c)) => (And8  n (Const8  <t> [c-1]))
  1171  (Mod16u <t> n (Const16 [c])) && ssa.IsPowerOfTwo(uint16(c)) => (And16 n (Const16 <t> [c-1]))
  1172  (Mod32u <t> n (Const32 [c])) && ssa.IsPowerOfTwo(uint32(c)) => (And32 n (Const32 <t> [c-1]))
  1173  (Mod64u <t> n (Const64 [c])) && ssa.IsPowerOfTwo(uint64(c)) => (And64 n (Const64 <t> [c-1]))
  1174  
  1175  // Signed non-negative mod by power of 2 constant.
  1176  // TODO: Replace ModN with ModNu in prove.
  1177  (Mod8  <t> n (Const8  [c])) && isNonNegative(n) && ssa.IsPowerOfTwo(c) => (And8  n (Const8  <t> [c-1]))
  1178  (Mod16 <t> n (Const16 [c])) && isNonNegative(n) && ssa.IsPowerOfTwo(c) => (And16 n (Const16 <t> [c-1]))
  1179  (Mod32 <t> n (Const32 [c])) && isNonNegative(n) && ssa.IsPowerOfTwo(c) => (And32 n (Const32 <t> [c-1]))
  1180  (Mod64 <t> n (Const64 [c])) && isNonNegative(n) && ssa.IsPowerOfTwo(c) => (And64 n (Const64 <t> [c-1]))
  1181  (Mod64 n (Const64 [-1<<63])) && isNonNegative(n)                   => n
  1182  
  1183  // Signed mod by negative constant.
  1184  (Mod8  <t> n (Const8  [c])) && c < 0 && c != -1<<7  => (Mod8  <t> n (Const8  <t> [-c]))
  1185  (Mod16 <t> n (Const16 [c])) && c < 0 && c != -1<<15 => (Mod16 <t> n (Const16 <t> [-c]))
  1186  (Mod32 <t> n (Const32 [c])) && c < 0 && c != -1<<31 => (Mod32 <t> n (Const32 <t> [-c]))
  1187  (Mod64 <t> n (Const64 [c])) && c < 0 && c != -1<<63 => (Mod64 <t> n (Const64 <t> [-c]))
  1188  
  1189  // All other mods by constants, do A%B = A-(A/B*B).
  1190  // This implements % with two * and a bunch of ancillary ops.
  1191  // One of the * is free if the user's code also computes A/B.
  1192  (Mod8   <t> x (Const8  [c])) && x.Op != ssaop.OpConst8  && (c > 0 || c == -1<<7)
  1193    => (Sub8  x (Mul8  <t> (Div8   <t> x (Const8  <t> [c])) (Const8  <t> [c])))
  1194  (Mod16  <t> x (Const16 [c])) && x.Op != ssaop.OpConst16 && (c > 0 || c == -1<<15)
  1195    => (Sub16 x (Mul16 <t> (Div16  <t> x (Const16 <t> [c])) (Const16 <t> [c])))
  1196  (Mod32  <t> x (Const32 [c])) && x.Op != ssaop.OpConst32 && (c > 0 || c == -1<<31)
  1197    => (Sub32 x (Mul32 <t> (Div32  <t> x (Const32 <t> [c])) (Const32 <t> [c])))
  1198  (Mod64  <t> x (Const64 [c])) && x.Op != ssaop.OpConst64 && (c > 0 || c == -1<<63)
  1199    => (Sub64 x (Mul64 <t> (Div64  <t> x (Const64 <t> [c])) (Const64 <t> [c])))
  1200  (Mod8u  <t> x (Const8  [c])) && x.Op != ssaop.OpConst8  && c != 0
  1201    => (Sub8  x (Mul8  <t> (Div8u  <t> x (Const8  <t> [c])) (Const8  <t> [c])))
  1202  (Mod16u <t> x (Const16 [c])) && x.Op != ssaop.OpConst16 && c != 0
  1203    => (Sub16 x (Mul16 <t> (Div16u <t> x (Const16 <t> [c])) (Const16 <t> [c])))
  1204  (Mod32u <t> x (Const32 [c])) && x.Op != ssaop.OpConst32 && c != 0
  1205    => (Sub32 x (Mul32 <t> (Div32u <t> x (Const32 <t> [c])) (Const32 <t> [c])))
  1206  (Mod64u <t> x (Const64 [c])) && x.Op != ssaop.OpConst64 && c != 0
  1207    => (Sub64 x (Mul64 <t> (Div64u <t> x (Const64 <t> [c])) (Const64 <t> [c])))
  1208  
  1209  // Set up for mod->mul+rot optimization in genericlateopt.rules.
  1210  // For architectures without rotates on less than 32-bits, promote to 32-bit.
  1211  // TODO: Also != 0 case?
  1212  (Eq8 (Mod8u x (Const8  [c])) (Const8 [0])) && x.Op != ssaop.OpConst8 && ssa.UdivisibleOK8(c) && !hasSmallRotate(config) =>
  1213  	(Eq32 (Mod32u <typ.UInt32> (ZeroExt8to32 <typ.UInt32> x) (Const32 <typ.UInt32> [int32(uint8(c))])) (Const32 <typ.UInt32> [0]))
  1214  (Eq16 (Mod16u x (Const16  [c])) (Const16 [0])) && x.Op != ssaop.OpConst16 && ssa.UdivisibleOK16(c) && !hasSmallRotate(config) =>
  1215  	(Eq32 (Mod32u <typ.UInt32> (ZeroExt16to32 <typ.UInt32> x) (Const32 <typ.UInt32> [int32(uint16(c))])) (Const32 <typ.UInt32> [0]))
  1216  (Eq8 (Mod8 x (Const8  [c])) (Const8 [0])) && x.Op != ssaop.OpConst8 && ssa.SdivisibleOK8(c) && !hasSmallRotate(config) =>
  1217  	(Eq32 (Mod32 <typ.Int32> (SignExt8to32 <typ.Int32> x) (Const32 <typ.Int32> [int32(c)])) (Const32 <typ.Int32> [0]))
  1218  (Eq16 (Mod16 x (Const16  [c])) (Const16 [0])) && x.Op != ssaop.OpConst16 && ssa.SdivisibleOK16(c) && !hasSmallRotate(config) =>
  1219  	(Eq32 (Mod32 <typ.Int32> (SignExt16to32 <typ.Int32> x) (Const32 <typ.Int32> [int32(c)])) (Const32 <typ.Int32> [0]))
  1220  
  1221  (Eq(8|16|32|64)  s:(Sub(8|16|32|64) x y) (Const(8|16|32|64) [0])) && s.Uses == 1 => (Eq(8|16|32|64)  x y)
  1222  (Neq(8|16|32|64) s:(Sub(8|16|32|64) x y) (Const(8|16|32|64) [0])) && s.Uses == 1 => (Neq(8|16|32|64) x y)
  1223  
  1224  // Optimize bitsets
  1225  (Eq(8|16|32|64) (And(8|16|32|64) <t> x (Const(8|16|32|64) <t> [y])) (Const(8|16|32|64) <t> [y])) && ssa.OneBit(y)
  1226    => (Neq(8|16|32|64) (And(8|16|32|64) <t> x (Const(8|16|32|64) <t> [y])) (Const(8|16|32|64) <t> [0]))
  1227  (Neq(8|16|32|64) (And(8|16|32|64) <t> x (Const(8|16|32|64) <t> [y])) (Const(8|16|32|64) <t> [y])) && ssa.OneBit(y)
  1228    => (Eq(8|16|32|64) (And(8|16|32|64) <t> x (Const(8|16|32|64) <t> [y])) (Const(8|16|32|64) <t> [0]))
  1229  
  1230  // Mark newly generated bounded shifts as bounded, for opt passes after prove.
  1231  (Lsh64x(8|16|32|64)  [false] x con:(Const(8|16|32|64) [c])) && 0 < c && c < 64 => (Lsh64x(8|16|32|64)  [true] x con)
  1232  (Rsh64x(8|16|32|64)  [false] x con:(Const(8|16|32|64) [c])) && 0 < c && c < 64 => (Rsh64x(8|16|32|64)  [true] x con)
  1233  (Rsh64Ux(8|16|32|64) [false] x con:(Const(8|16|32|64) [c])) && 0 < c && c < 64 => (Rsh64Ux(8|16|32|64) [true] x con)
  1234  (Lsh32x(8|16|32|64)  [false] x con:(Const(8|16|32|64) [c])) && 0 < c && c < 32 => (Lsh32x(8|16|32|64)  [true] x con)
  1235  (Rsh32x(8|16|32|64)  [false] x con:(Const(8|16|32|64) [c])) && 0 < c && c < 32 => (Rsh32x(8|16|32|64)  [true] x con)
  1236  (Rsh32Ux(8|16|32|64) [false] x con:(Const(8|16|32|64) [c])) && 0 < c && c < 32 => (Rsh32Ux(8|16|32|64) [true] x con)
  1237  (Lsh16x(8|16|32|64)  [false] x con:(Const(8|16|32|64) [c])) && 0 < c && c < 16 => (Lsh16x(8|16|32|64)  [true] x con)
  1238  (Rsh16x(8|16|32|64)  [false] x con:(Const(8|16|32|64) [c])) && 0 < c && c < 16 => (Rsh16x(8|16|32|64)  [true] x con)
  1239  (Rsh16Ux(8|16|32|64) [false] x con:(Const(8|16|32|64) [c])) && 0 < c && c < 16 => (Rsh16Ux(8|16|32|64) [true] x con)
  1240  (Lsh8x(8|16|32|64)   [false] x con:(Const(8|16|32|64) [c])) && 0 < c && c < 8  => (Lsh8x(8|16|32|64)   [true] x con)
  1241  (Rsh8x(8|16|32|64)   [false] x con:(Const(8|16|32|64) [c])) && 0 < c && c < 8  => (Rsh8x(8|16|32|64)   [true] x con)
  1242  (Rsh8Ux(8|16|32|64)  [false] x con:(Const(8|16|32|64) [c])) && 0 < c && c < 8  => (Rsh8Ux(8|16|32|64)  [true] x con)
  1243  
  1244  // Reassociate expressions involving
  1245  // constants such that constants come first,
  1246  // exposing obvious constant-folding opportunities.
  1247  // Reassociate (op (op y C) x) to (op C (op x y)) or similar, where C
  1248  // is constant, which pushes constants to the outside
  1249  // of the expression. At that point, any constant-folding
  1250  // opportunities should be obvious.
  1251  // Note: don't include AddPtr here! In order to maintain the
  1252  // invariant that pointers must stay within the pointed-to object,
  1253  // we can't pull part of a pointer computation above the AddPtr.
  1254  // See issue 37881.
  1255  // Note: we don't need to handle any (x-C) cases because we already rewrite
  1256  // (x-C) to (x+(-C)).
  1257  
  1258  // x + (C + z) -> C + (x + z)
  1259  (Add64 (Add64 i:(Const64 <t>) z) x) && (z.Op != ssaop.OpConst64 && x.Op != ssaop.OpConst64) => (Add64 i (Add64 <t> z x))
  1260  (Add32 (Add32 i:(Const32 <t>) z) x) && (z.Op != ssaop.OpConst32 && x.Op != ssaop.OpConst32) => (Add32 i (Add32 <t> z x))
  1261  (Add16 (Add16 i:(Const16 <t>) z) x) && (z.Op != ssaop.OpConst16 && x.Op != ssaop.OpConst16) => (Add16 i (Add16 <t> z x))
  1262  (Add8  (Add8  i:(Const8  <t>) z) x) && (z.Op != ssaop.OpConst8  && x.Op != ssaop.OpConst8)  => (Add8  i (Add8  <t> z x))
  1263  
  1264  // x + (C - z) -> C + (x - z)
  1265  (Add64 (Sub64 i:(Const64 <t>) z) x) && (z.Op != ssaop.OpConst64 && x.Op != ssaop.OpConst64) => (Add64 i (Sub64 <t> x z))
  1266  (Add32 (Sub32 i:(Const32 <t>) z) x) && (z.Op != ssaop.OpConst32 && x.Op != ssaop.OpConst32) => (Add32 i (Sub32 <t> x z))
  1267  (Add16 (Sub16 i:(Const16 <t>) z) x) && (z.Op != ssaop.OpConst16 && x.Op != ssaop.OpConst16) => (Add16 i (Sub16 <t> x z))
  1268  (Add8  (Sub8  i:(Const8  <t>) z) x) && (z.Op != ssaop.OpConst8  && x.Op != ssaop.OpConst8)  => (Add8  i (Sub8  <t> x z))
  1269  
  1270  // x - (C - z) -> x + (z - C) -> (x + z) - C
  1271  (Sub64 x (Sub64 i:(Const64 <t>) z)) && (z.Op != ssaop.OpConst64 && x.Op != ssaop.OpConst64) => (Sub64 (Add64 <t> x z) i)
  1272  (Sub32 x (Sub32 i:(Const32 <t>) z)) && (z.Op != ssaop.OpConst32 && x.Op != ssaop.OpConst32) => (Sub32 (Add32 <t> x z) i)
  1273  (Sub16 x (Sub16 i:(Const16 <t>) z)) && (z.Op != ssaop.OpConst16 && x.Op != ssaop.OpConst16) => (Sub16 (Add16 <t> x z) i)
  1274  (Sub8  x (Sub8  i:(Const8  <t>) z)) && (z.Op != ssaop.OpConst8  && x.Op != ssaop.OpConst8)  => (Sub8  (Add8  <t> x z) i)
  1275  
  1276  // x - (z + C) -> x + (-z - C) -> (x - z) - C
  1277  (Sub64 x (Add64 z i:(Const64 <t>))) && (z.Op != ssaop.OpConst64 && x.Op != ssaop.OpConst64) => (Sub64 (Sub64 <t> x z) i)
  1278  (Sub32 x (Add32 z i:(Const32 <t>))) && (z.Op != ssaop.OpConst32 && x.Op != ssaop.OpConst32) => (Sub32 (Sub32 <t> x z) i)
  1279  (Sub16 x (Add16 z i:(Const16 <t>))) && (z.Op != ssaop.OpConst16 && x.Op != ssaop.OpConst16) => (Sub16 (Sub16 <t> x z) i)
  1280  (Sub8  x (Add8  z i:(Const8  <t>))) && (z.Op != ssaop.OpConst8  && x.Op != ssaop.OpConst8)  => (Sub8 (Sub8  <t> x z) i)
  1281  
  1282  // (C - z) - x -> C - (z + x)
  1283  (Sub64 (Sub64 i:(Const64 <t>) z) x) && (z.Op != ssaop.OpConst64 && x.Op != ssaop.OpConst64) => (Sub64 i (Add64 <t> z x))
  1284  (Sub32 (Sub32 i:(Const32 <t>) z) x) && (z.Op != ssaop.OpConst32 && x.Op != ssaop.OpConst32) => (Sub32 i (Add32 <t> z x))
  1285  (Sub16 (Sub16 i:(Const16 <t>) z) x) && (z.Op != ssaop.OpConst16 && x.Op != ssaop.OpConst16) => (Sub16 i (Add16 <t> z x))
  1286  (Sub8  (Sub8  i:(Const8  <t>) z) x) && (z.Op != ssaop.OpConst8  && x.Op != ssaop.OpConst8)  => (Sub8  i (Add8  <t> z x))
  1287  
  1288  // (z + C) -x -> C + (z - x)
  1289  (Sub64 (Add64 z i:(Const64 <t>)) x) && (z.Op != ssaop.OpConst64 && x.Op != ssaop.OpConst64) => (Add64 i (Sub64 <t> z x))
  1290  (Sub32 (Add32 z i:(Const32 <t>)) x) && (z.Op != ssaop.OpConst32 && x.Op != ssaop.OpConst32) => (Add32 i (Sub32 <t> z x))
  1291  (Sub16 (Add16 z i:(Const16 <t>)) x) && (z.Op != ssaop.OpConst16 && x.Op != ssaop.OpConst16) => (Add16 i (Sub16 <t> z x))
  1292  (Sub8  (Add8  z i:(Const8  <t>)) x) && (z.Op != ssaop.OpConst8  && x.Op != ssaop.OpConst8)  => (Add8  i (Sub8  <t> z x))
  1293  
  1294  // x & (C & z) -> C & (x & z)
  1295  (And64 (And64 i:(Const64 <t>) z) x) && (z.Op != ssaop.OpConst64 && x.Op != ssaop.OpConst64) => (And64 i (And64 <t> z x))
  1296  (And32 (And32 i:(Const32 <t>) z) x) && (z.Op != ssaop.OpConst32 && x.Op != ssaop.OpConst32) => (And32 i (And32 <t> z x))
  1297  (And16 (And16 i:(Const16 <t>) z) x) && (z.Op != ssaop.OpConst16 && x.Op != ssaop.OpConst16) => (And16 i (And16 <t> z x))
  1298  (And8  (And8  i:(Const8  <t>) z) x) && (z.Op != ssaop.OpConst8  && x.Op != ssaop.OpConst8)  => (And8  i (And8  <t> z x))
  1299  
  1300  // x | (C | z) -> C | (x | z)
  1301  (Or64 (Or64 i:(Const64 <t>) z) x) && (z.Op != ssaop.OpConst64 && x.Op != ssaop.OpConst64) => (Or64 i (Or64 <t> z x))
  1302  (Or32 (Or32 i:(Const32 <t>) z) x) && (z.Op != ssaop.OpConst32 && x.Op != ssaop.OpConst32) => (Or32 i (Or32 <t> z x))
  1303  (Or16 (Or16 i:(Const16 <t>) z) x) && (z.Op != ssaop.OpConst16 && x.Op != ssaop.OpConst16) => (Or16 i (Or16 <t> z x))
  1304  (Or8  (Or8  i:(Const8  <t>) z) x) && (z.Op != ssaop.OpConst8  && x.Op != ssaop.OpConst8)  => (Or8  i (Or8  <t> z x))
  1305  
  1306  // x ^ (C ^ z) -> C ^ (x ^ z)
  1307  (Xor64 (Xor64 i:(Const64 <t>) z) x) && (z.Op != ssaop.OpConst64 && x.Op != ssaop.OpConst64) => (Xor64 i (Xor64 <t> z x))
  1308  (Xor32 (Xor32 i:(Const32 <t>) z) x) && (z.Op != ssaop.OpConst32 && x.Op != ssaop.OpConst32) => (Xor32 i (Xor32 <t> z x))
  1309  (Xor16 (Xor16 i:(Const16 <t>) z) x) && (z.Op != ssaop.OpConst16 && x.Op != ssaop.OpConst16) => (Xor16 i (Xor16 <t> z x))
  1310  (Xor8  (Xor8  i:(Const8  <t>) z) x) && (z.Op != ssaop.OpConst8  && x.Op != ssaop.OpConst8)  => (Xor8  i (Xor8  <t> z x))
  1311  
  1312  // x * (D * z) = D * (x * z)
  1313  (Mul64 (Mul64 i:(Const64 <t>) z) x) && (z.Op != ssaop.OpConst64 && x.Op != ssaop.OpConst64) => (Mul64 i (Mul64 <t> x z))
  1314  (Mul32 (Mul32 i:(Const32 <t>) z) x) && (z.Op != ssaop.OpConst32 && x.Op != ssaop.OpConst32) => (Mul32 i (Mul32 <t> x z))
  1315  (Mul16 (Mul16 i:(Const16 <t>) z) x) && (z.Op != ssaop.OpConst16 && x.Op != ssaop.OpConst16) => (Mul16 i (Mul16 <t> x z))
  1316  (Mul8  (Mul8  i:(Const8  <t>) z) x) && (z.Op != ssaop.OpConst8  && x.Op != ssaop.OpConst8)  => (Mul8  i (Mul8  <t> x z))
  1317  
  1318  // C + (D + x) -> (C + D) + x
  1319  (Add64 (Const64 <t> [c]) (Add64 (Const64 <t> [d]) x)) => (Add64 (Const64 <t> [c+d]) x)
  1320  (Add32 (Const32 <t> [c]) (Add32 (Const32 <t> [d]) x)) => (Add32 (Const32 <t> [c+d]) x)
  1321  (Add16 (Const16 <t> [c]) (Add16 (Const16 <t> [d]) x)) => (Add16 (Const16 <t> [c+d]) x)
  1322  (Add8  (Const8  <t> [c]) (Add8  (Const8  <t> [d]) x)) => (Add8  (Const8  <t> [c+d]) x)
  1323  
  1324  // C + (D - x) -> (C + D) - x
  1325  (Add64 (Const64 <t> [c]) (Sub64 (Const64 <t> [d]) x)) => (Sub64 (Const64 <t> [c+d]) x)
  1326  (Add32 (Const32 <t> [c]) (Sub32 (Const32 <t> [d]) x)) => (Sub32 (Const32 <t> [c+d]) x)
  1327  (Add16 (Const16 <t> [c]) (Sub16 (Const16 <t> [d]) x)) => (Sub16 (Const16 <t> [c+d]) x)
  1328  (Add8  (Const8  <t> [c]) (Sub8  (Const8  <t> [d]) x)) => (Sub8  (Const8  <t> [c+d]) x)
  1329  
  1330  // C - (D - x) -> (C - D) + x
  1331  (Sub64 (Const64 <t> [c]) (Sub64 (Const64 <t> [d]) x)) => (Add64 (Const64 <t> [c-d]) x)
  1332  (Sub32 (Const32 <t> [c]) (Sub32 (Const32 <t> [d]) x)) => (Add32 (Const32 <t> [c-d]) x)
  1333  (Sub16 (Const16 <t> [c]) (Sub16 (Const16 <t> [d]) x)) => (Add16 (Const16 <t> [c-d]) x)
  1334  (Sub8  (Const8  <t> [c]) (Sub8  (Const8  <t> [d]) x)) => (Add8  (Const8  <t> [c-d]) x)
  1335  
  1336  // C - (D + x) -> (C - D) - x
  1337  (Sub64 (Const64 <t> [c]) (Add64 (Const64 <t> [d]) x)) => (Sub64 (Const64 <t> [c-d]) x)
  1338  (Sub32 (Const32 <t> [c]) (Add32 (Const32 <t> [d]) x)) => (Sub32 (Const32 <t> [c-d]) x)
  1339  (Sub16 (Const16 <t> [c]) (Add16 (Const16 <t> [d]) x)) => (Sub16 (Const16 <t> [c-d]) x)
  1340  (Sub8  (Const8  <t> [c]) (Add8  (Const8  <t> [d]) x)) => (Sub8  (Const8  <t> [c-d]) x)
  1341  
  1342  // C & (D & x) -> (C & D) & x
  1343  (And64 (Const64 <t> [c]) (And64 (Const64 <t> [d]) x)) => (And64 (Const64 <t> [c&d]) x)
  1344  (And32 (Const32 <t> [c]) (And32 (Const32 <t> [d]) x)) => (And32 (Const32 <t> [c&d]) x)
  1345  (And16 (Const16 <t> [c]) (And16 (Const16 <t> [d]) x)) => (And16 (Const16 <t> [c&d]) x)
  1346  (And8  (Const8  <t> [c]) (And8  (Const8  <t> [d]) x)) => (And8  (Const8  <t> [c&d]) x)
  1347  
  1348  // C | (D | x) -> (C | D) | x
  1349  (Or64 (Const64 <t> [c]) (Or64 (Const64 <t> [d]) x)) => (Or64 (Const64 <t> [c|d]) x)
  1350  (Or32 (Const32 <t> [c]) (Or32 (Const32 <t> [d]) x)) => (Or32 (Const32 <t> [c|d]) x)
  1351  (Or16 (Const16 <t> [c]) (Or16 (Const16 <t> [d]) x)) => (Or16 (Const16 <t> [c|d]) x)
  1352  (Or8  (Const8  <t> [c]) (Or8  (Const8  <t> [d]) x)) => (Or8  (Const8  <t> [c|d]) x)
  1353  
  1354  // C ^ (D ^ x) -> (C ^ D) ^ x
  1355  (Xor64 (Const64 <t> [c]) (Xor64 (Const64 <t> [d]) x)) => (Xor64 (Const64 <t> [c^d]) x)
  1356  (Xor32 (Const32 <t> [c]) (Xor32 (Const32 <t> [d]) x)) => (Xor32 (Const32 <t> [c^d]) x)
  1357  (Xor16 (Const16 <t> [c]) (Xor16 (Const16 <t> [d]) x)) => (Xor16 (Const16 <t> [c^d]) x)
  1358  (Xor8  (Const8  <t> [c]) (Xor8  (Const8  <t> [d]) x)) => (Xor8  (Const8  <t> [c^d]) x)
  1359  
  1360  // C * (D * x) = (C * D) * x
  1361  // Allow constant folding for single uses while preserving shared power-of-2 multiplies for scaled-index addressing.
  1362  // See issue 80639 for additional details.
  1363  (Mul64 (Const64 <t> [c]) m:(Mul64 (Const64 <t> [d]) x)) && (!ssa.IsPowerOfTwo(c) || m.Uses == 1) => (Mul64 (Const64 <t> [c*d]) x)
  1364  (Mul32 (Const32 <t> [c]) m:(Mul32 (Const32 <t> [d]) x)) && (!ssa.IsPowerOfTwo(c) || m.Uses == 1) => (Mul32 (Const32 <t> [c*d]) x)
  1365  (Mul16 (Const16 <t> [c]) m:(Mul16 (Const16 <t> [d]) x)) && (!ssa.IsPowerOfTwo(c) || m.Uses == 1) => (Mul16 (Const16 <t> [c*d]) x)
  1366  (Mul8  (Const8  <t> [c]) m:(Mul8  (Const8  <t> [d]) x)) && (!ssa.IsPowerOfTwo(c) || m.Uses == 1) => (Mul8  (Const8  <t> [c*d]) x)
  1367  
  1368  
  1369  // floating point optimizations
  1370  (Mul(32|64)F x (Const(32|64)F [1])) => x
  1371  (Mul32F x (Const32F [-1])) => (Neg32F x)
  1372  (Mul64F x (Const64F [-1])) => (Neg64F x)
  1373  (Mul32F x (Const32F [2])) => (Add32F x x)
  1374  (Mul64F x (Const64F [2])) => (Add64F x x)
  1375  
  1376  (Div32F x (Const32F <t> [c])) && reciprocalExact32(c) => (Mul32F x (Const32F <t> [1/c]))
  1377  (Div64F x (Const64F <t> [c])) && reciprocalExact64(c) => (Mul64F x (Const64F <t> [1/c]))
  1378  
  1379  // rewrite single-precision sqrt expression "float32(math.Sqrt(float64(x)))"
  1380  (Cvt64Fto32F sqrt0:(Sqrt (Cvt32Fto64F x))) && sqrt0.Uses==1 => (Sqrt32 x)
  1381  
  1382  (Sqrt (Const64F [c])) && !math.IsNaN(math.Sqrt(c)) => (Const64F [math.Sqrt(c)])
  1383  
  1384  // for rewriting constant folded math/bits ops
  1385  (Select0 (MakeTuple x y)) => x
  1386  (Select1 (MakeTuple x y)) => y
  1387  
  1388  // for rewriting results of some late-expanded rewrites (below)
  1389  (SelectN [n] m:(MakeResult ___)) => m.Args[n]
  1390  
  1391  // TODO(matloob): Try out having non-zeroing mallocs for prointerless
  1392  // memory, and leaving the zeroing here. Then the compiler can remove
  1393  // the zeroing if the user has explicit writes to the whole object.
  1394  
  1395  // for late-expanded calls, recognize newobject and remove zeroing and nilchecks
  1396  (Zero (SelectN [0] call:(StaticLECall ___)) mem:(SelectN [1] call))
  1397  	&& isMalloc(call.Aux)
  1398  	=> mem
  1399  
  1400  (Store (SelectN [0] call:(StaticLECall ___)) x mem:(SelectN [1] call))
  1401  	&& ssa.IsConstZero(x)
  1402  	&& isMalloc(call.Aux)
  1403  	=> mem
  1404  
  1405  (Store (OffPtr (SelectN [0] call:(StaticLECall ___))) x mem:(SelectN [1] call))
  1406  	&& ssa.IsConstZero(x)
  1407  	&& isMalloc(call.Aux)
  1408  	=> mem
  1409  
  1410  (NilCheck ptr:(SelectN [0] call:(StaticLECall ___)) _)
  1411  	&& isMalloc(call.Aux)
  1412  	&& warnRule(fe.Debug_checknil(), v, "removed nil check")
  1413  	=> ptr
  1414  
  1415  (NilCheck ptr:(OffPtr (SelectN [0] call:(StaticLECall ___))) _)
  1416  	&& isMalloc(call.Aux)
  1417  	&& warnRule(fe.Debug_checknil(), v, "removed nil check")
  1418  	=> ptr
  1419  
  1420  // Addresses of globals are always non-nil.
  1421  (NilCheck          ptr:(Addr {_} (SB))    _) => ptr
  1422  (NilCheck ptr:(Convert (Addr {_} (SB)) _) _) => ptr
  1423  
  1424  // Addresses of locals are always non-nil.
  1425  (NilCheck ptr:(LocalAddr _ _) _)
  1426  	&& warnRule(fe.Debug_checknil(), v, "removed nil check")
  1427  	=> ptr
  1428  
  1429  // .dict args are always non-nil.
  1430  (NilCheck ptr:(Arg {sym}) _) && isDictArgSym(sym) => ptr
  1431  
  1432  // Nil checks of nil checks are redundant.
  1433  // See comment at the end of https://go-review.googlesource.com/c/go/+/537775.
  1434  (NilCheck ptr:(NilCheck _ _) _ ) => ptr
  1435  
  1436  // for late-expanded calls, recognize memequal applied to a single constant byte
  1437  // Support is limited by [1-8] byte sizes
  1438  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [1]) mem)
  1439    && ssa.IsSameCall(callAux, "runtime.memequal")
  1440    && ssa.SymIsRO(scon)
  1441    => (MakeResult (Eq8 (Load <typ.Int8> sptr mem) (Const8 <typ.Int8> [int8(ssa.Read8(scon,0))])) mem)
  1442  
  1443  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [1]) mem)
  1444    && ssa.IsSameCall(callAux, "runtime.memequal")
  1445    && ssa.SymIsRO(scon)
  1446    => (MakeResult (Eq8 (Load <typ.Int8> sptr mem) (Const8 <typ.Int8> [int8(ssa.Read8(scon,0))])) mem)
  1447  
  1448  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [2]) mem)
  1449    && ssa.IsSameCall(callAux, "runtime.memequal")
  1450    && ssa.SymIsRO(scon)
  1451    && canLoadUnaligned(config)
  1452    => (MakeResult (Eq16 (Load <typ.Int16> sptr mem) (Const16 <typ.Int16> [int16(ssa.Read16(scon,0,config.Ctxt.Arch.ByteOrder))])) mem)
  1453  
  1454  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [2]) mem)
  1455    && ssa.IsSameCall(callAux, "runtime.memequal")
  1456    && ssa.SymIsRO(scon)
  1457    && canLoadUnaligned(config)
  1458    => (MakeResult (Eq16 (Load <typ.Int16> sptr mem) (Const16 <typ.Int16> [int16(ssa.Read16(scon,0,config.Ctxt.Arch.ByteOrder))])) mem)
  1459  
  1460  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [4]) mem)
  1461    && ssa.IsSameCall(callAux, "runtime.memequal")
  1462    && ssa.SymIsRO(scon)
  1463    && canLoadUnaligned(config)
  1464    => (MakeResult (Eq32 (Load <typ.Int32> sptr mem) (Const32 <typ.Int32> [int32(ssa.Read32(scon,0,config.Ctxt.Arch.ByteOrder))])) mem)
  1465  
  1466  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [4]) mem)
  1467    && ssa.IsSameCall(callAux, "runtime.memequal")
  1468    && ssa.SymIsRO(scon)
  1469    && canLoadUnaligned(config)
  1470    => (MakeResult (Eq32 (Load <typ.Int32> sptr mem) (Const32 <typ.Int32> [int32(ssa.Read32(scon,0,config.Ctxt.Arch.ByteOrder))])) mem)
  1471  
  1472  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [8]) mem)
  1473    && ssa.IsSameCall(callAux, "runtime.memequal")
  1474    && ssa.SymIsRO(scon)
  1475    && canLoadUnaligned(config) && config.PtrSize == 8
  1476    => (MakeResult (Eq64 (Load <typ.Int64> sptr mem) (Const64 <typ.Int64> [int64(ssa.Read64(scon,0,config.Ctxt.Arch.ByteOrder))])) mem)
  1477  
  1478  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [8]) mem)
  1479    && ssa.IsSameCall(callAux, "runtime.memequal")
  1480    && ssa.SymIsRO(scon)
  1481    && canLoadUnaligned(config) && config.PtrSize == 8
  1482    => (MakeResult (Eq64 (Load <typ.Int64> sptr mem) (Const64 <typ.Int64> [int64(ssa.Read64(scon,0,config.Ctxt.Arch.ByteOrder))])) mem)
  1483  
  1484  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [3]) mem)
  1485    && ssa.IsSameCall(callAux, "runtime.memequal")
  1486    && ssa.SymIsRO(scon)
  1487    && canLoadUnaligned(config) =>
  1488    (MakeResult
  1489      (Eq32
  1490        (Or32 <typ.Int32>
  1491          (ZeroExt16to32 <typ.Int32> (Load <typ.Int16> sptr mem))
  1492          (Lsh32x32 <typ.Int32>
  1493            (ZeroExt8to32 <typ.Int32> (Load <typ.Int8> (OffPtr <typ.BytePtr> [2] sptr) mem))
  1494            (Const32 <typ.Int32> [16])))
  1495        (Const32 <typ.Int32> [int32(uint32(ssa.Read16(scon,0,config.Ctxt.Arch.ByteOrder))|(uint32(ssa.Read8(scon,2))<<16))]))
  1496      mem)
  1497  
  1498  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [3]) mem)
  1499    && ssa.IsSameCall(callAux, "runtime.memequal")
  1500    && ssa.SymIsRO(scon)
  1501    && canLoadUnaligned(config) =>
  1502    (MakeResult
  1503      (Eq32
  1504        (Or32 <typ.Int32>
  1505          (ZeroExt16to32 <typ.Int32> (Load <typ.Int16> sptr mem))
  1506          (Lsh32x32 <typ.Int32>
  1507            (ZeroExt8to32 <typ.Int32> (Load <typ.Int8> (OffPtr <typ.BytePtr> [2] sptr) mem))
  1508            (Const32 <typ.Int32> [16])))
  1509        (Const32 <typ.Int32> [int32(uint32(ssa.Read16(scon,0,config.Ctxt.Arch.ByteOrder))|(uint32(ssa.Read8(scon,2))<<16))]))
  1510      mem)
  1511  
  1512  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [5]) mem)
  1513    && ssa.IsSameCall(callAux, "runtime.memequal")
  1514    && ssa.SymIsRO(scon)
  1515    && canLoadUnaligned(config) && config.PtrSize == 8 =>
  1516    (MakeResult
  1517      (Eq64
  1518        (Or64 <typ.Int64>
  1519          (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> sptr mem))
  1520          (Lsh64x64 <typ.Int64>
  1521            (ZeroExt8to64 <typ.Int64> (Load <typ.Int8> (OffPtr <typ.BytePtr> [4] sptr) mem))
  1522            (Const64 <typ.Int64> [32])))
  1523        (Const64 <typ.Int64> [int64(uint64(ssa.Read32(scon,0,config.Ctxt.Arch.ByteOrder))|(uint64(ssa.Read8(scon,4))<<32))]))
  1524      mem)
  1525  
  1526  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [5]) mem)
  1527    && ssa.IsSameCall(callAux, "runtime.memequal")
  1528    && ssa.SymIsRO(scon)
  1529    && canLoadUnaligned(config) && config.PtrSize == 8 =>
  1530    (MakeResult
  1531      (Eq64
  1532        (Or64 <typ.Int64>
  1533          (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> sptr mem))
  1534          (Lsh64x64 <typ.Int64>
  1535            (ZeroExt8to64 <typ.Int64> (Load <typ.Int8> (OffPtr <typ.BytePtr> [4] sptr) mem))
  1536            (Const64 <typ.Int64> [32])))
  1537        (Const64 <typ.Int64> [int64(uint64(ssa.Read32(scon,0,config.Ctxt.Arch.ByteOrder))|(uint64(ssa.Read8(scon,4))<<32))]))
  1538      mem)
  1539  
  1540  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [6]) mem)
  1541    && ssa.IsSameCall(callAux, "runtime.memequal")
  1542    && ssa.SymIsRO(scon)
  1543    && canLoadUnaligned(config) && config.PtrSize == 8 =>
  1544    (MakeResult
  1545      (Eq64
  1546        (Or64 <typ.Int64>
  1547          (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> sptr mem))
  1548          (Lsh64x64 <typ.Int64>
  1549            (ZeroExt16to64 <typ.Int64> (Load <typ.Int16> (OffPtr <typ.BytePtr> [4] sptr) mem))
  1550            (Const64 <typ.Int64> [32])))
  1551        (Const64 <typ.Int64> [int64(uint64(ssa.Read32(scon,0,config.Ctxt.Arch.ByteOrder))|(uint64(ssa.Read16(scon,4,config.Ctxt.Arch.ByteOrder))<<32))]))
  1552      mem)
  1553  
  1554  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [6]) mem)
  1555    && ssa.IsSameCall(callAux, "runtime.memequal")
  1556    && ssa.SymIsRO(scon)
  1557    && canLoadUnaligned(config) && config.PtrSize == 8 =>
  1558    (MakeResult
  1559      (Eq64
  1560        (Or64 <typ.Int64>
  1561          (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> sptr mem))
  1562          (Lsh64x64 <typ.Int64>
  1563            (ZeroExt16to64 <typ.Int64> (Load <typ.Int16> (OffPtr <typ.BytePtr> [4] sptr) mem))
  1564            (Const64 <typ.Int64> [32])))
  1565        (Const64 <typ.Int64> [int64(uint64(ssa.Read32(scon,0,config.Ctxt.Arch.ByteOrder))|(uint64(ssa.Read16(scon,4,config.Ctxt.Arch.ByteOrder))<<32))]))
  1566      mem)
  1567  
  1568  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [7]) mem)
  1569    && ssa.IsSameCall(callAux, "runtime.memequal")
  1570    && ssa.SymIsRO(scon)
  1571    && canLoadUnaligned(config) && config.PtrSize == 8 =>
  1572    (MakeResult
  1573      (Eq64
  1574        (Or64 <typ.Int64>
  1575          (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> sptr mem))
  1576          (Lsh64x64 <typ.Int64>
  1577            (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> (OffPtr <typ.BytePtr> [3] sptr) mem))
  1578            (Const64 <typ.Int64> [32])))
  1579        (Const64 <typ.Int64> [int64(uint64(ssa.Read32(scon,0,config.Ctxt.Arch.ByteOrder))|(uint64(ssa.Read32(scon,3,config.Ctxt.Arch.ByteOrder))<<32))]))
  1580      mem)
  1581  
  1582  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [7]) mem)
  1583    && ssa.IsSameCall(callAux, "runtime.memequal")
  1584    && ssa.SymIsRO(scon)
  1585    && canLoadUnaligned(config) && config.PtrSize == 8 =>
  1586    (MakeResult
  1587      (Eq64
  1588        (Or64 <typ.Int64>
  1589          (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> sptr mem))
  1590          (Lsh64x64 <typ.Int64>
  1591            (ZeroExt32to64 <typ.Int64> (Load <typ.Int32> (OffPtr <typ.BytePtr> [3] sptr) mem))
  1592            (Const64 <typ.Int64> [32])))
  1593        (Const64 <typ.Int64> [int64(uint64(ssa.Read32(scon,0,config.Ctxt.Arch.ByteOrder))|(uint64(ssa.Read32(scon,3,config.Ctxt.Arch.ByteOrder))<<32))]))
  1594      mem)
  1595  
  1596  (StaticLECall {callAux} _ _ (Const64 [0]) mem)
  1597    && ssa.IsSameCall(callAux, "runtime.memequal")
  1598    => (MakeResult (ConstBool <typ.Bool> [true]) mem)
  1599  
  1600  (Static(Call|LECall) {callAux} p q _ mem)
  1601    && ssa.IsSameCall(callAux, "runtime.memequal")
  1602    && ssa.IsSamePtr(p, q)
  1603    => (MakeResult (ConstBool <typ.Bool> [true]) mem)
  1604  
  1605  (MemEq sptr tptr (Const64 [1]) mem)
  1606    => (Eq8 (Load <typ.Int8> sptr mem) (Load <typ.Int8> tptr mem))
  1607  
  1608  (Load <typ.Int8> sptr:(Addr {scon} (SB)) mem)
  1609    && ssa.SymIsRO(scon)
  1610    => (Const8 <typ.Int8> [int8(ssa.Read8(scon,0))])
  1611  
  1612  (MemEq sptr tptr (Const64 [2]) mem)
  1613    && canLoadUnaligned(config)
  1614    => (Eq16 (Load <typ.Int16> sptr mem) (Load <typ.Int16> tptr mem))
  1615  
  1616  (Load <typ.Int16> sptr:(Addr {scon} (SB)) mem)
  1617    && ssa.SymIsRO(scon)
  1618    => (Const16 <typ.Int16> [int16(ssa.Read16(scon,0,config.Ctxt.Arch.ByteOrder))])
  1619  
  1620  (MemEq sptr tptr (Const64 [4]) mem)
  1621    && canLoadUnaligned(config)
  1622    => (Eq32 (Load <typ.Int32> sptr mem) (Load <typ.Int32> tptr mem))
  1623  
  1624  (Load <typ.Int32> sptr:(Addr {scon} (SB)) mem)
  1625    && ssa.SymIsRO(scon)
  1626    => (Const32 <typ.Int32> [int32(ssa.Read32(scon,0,config.Ctxt.Arch.ByteOrder))])
  1627  
  1628  (MemEq sptr tptr (Const64 [8]) mem)
  1629    && canLoadUnaligned(config) && config.PtrSize == 8
  1630    => (Eq64 (Load <typ.Int64> sptr mem) (Load <typ.Int64> tptr mem))
  1631  
  1632  (Load <typ.Int64> sptr:(Addr {scon} (SB)) mem)
  1633    && ssa.SymIsRO(scon)
  1634    => (Const64 <typ.Int64> [int64(ssa.Read64(scon,0,config.Ctxt.Arch.ByteOrder))])
  1635  
  1636  (MemEq _ _ (Const64 [0]) _) => (ConstBool <typ.Bool> [true])
  1637  
  1638  (MemEq p q _ _) && ssa.IsSamePtr(p, q) => (ConstBool <typ.Bool> [true])
  1639  
  1640  // 3-32 bytes memeq (enabled only with support of unaligned loads and 8-byte max word size)
  1641  
  1642  (MemEq p q (Const64 [c]) mem)
  1643    && (c == 3 || c == 5 || c == 9 || c == 17)
  1644    && canLoadUnaligned(config)
  1645    && config.RegSize == 8
  1646    => (AndB (MemEq p q (Const64 <typ.Int64> [c-1]) mem)
  1647             (Eq8 (Load <typ.Int8> (OffPtr <p.Type> p [c-1]) mem) (Load <typ.Int8> (OffPtr <q.Type> q [c-1]) mem)))
  1648  
  1649  (MemEq p q (Const64 [c]) mem)
  1650    && (c == 6 || c == 10 || c == 18)
  1651    && canLoadUnaligned(config)
  1652    && config.RegSize == 8
  1653    => (AndB (MemEq p q (Const64 <typ.Int64> [c-2]) mem)
  1654             (Eq16 (Load <typ.Int16> (OffPtr <p.Type> p [c-2]) mem) (Load <typ.Int16> (OffPtr <q.Type> q [c-2]) mem)))
  1655  
  1656  (MemEq p q (Const64 [c]) mem)
  1657    && (c == 7 || c == 11 || c == 19 || c == 20)
  1658    && canLoadUnaligned(config)
  1659    && config.RegSize == 8
  1660    => (AndB (MemEq p q (Const64 <typ.Int64> [min(c-3,16)]) mem)
  1661             (Eq32 (Load <typ.Int32> (OffPtr <p.Type> p [c-4]) mem) (Load <typ.Int32> (OffPtr <q.Type> q [c-4]) mem)))
  1662  
  1663  (MemEq p q (Const64 [c]) mem)
  1664    && ((c >= 12 && c <= 16) || (c >= 21 && c <= 24))
  1665    && canLoadUnaligned(config)
  1666    && config.RegSize == 8
  1667    => (AndB (MemEq p q (Const64 <typ.Int64> [8 + int64(bool2int(c>16))*8]) mem)
  1668             (Eq64 (Load <typ.Int64> (OffPtr <p.Type> p [c-8]) mem) (Load <typ.Int64> (OffPtr <q.Type> q [c-8]) mem)))
  1669  
  1670  (MemEq p q (Const64 [c]) mem)
  1671    && c >= 25 && c <= 32
  1672    && canLoadUnaligned(config)
  1673    && config.RegSize == 8
  1674    => (AndB (MemEq p q (Const64 <typ.Int64> [16]) mem)
  1675             (MemEq (OffPtr <p.Type> p [16]) (OffPtr <q.Type> q [16]) (Const64 <typ.Int64> [c-16]) mem))
  1676  
  1677  // Turn known-size calls to memclrNoHeapPointers into a Zero.
  1678  // Note that we are using types.Types[types.TUINT8] instead of sptr.Type.Elem() - see issue 55122 and CL 431496 for more details.
  1679  (SelectN [0] call:(StaticCall {sym} sptr (Const(64|32) [c]) mem))
  1680    && isInlinableMemclr(config, int64(c))
  1681    && ssa.IsSameCall(sym, "runtime.memclrNoHeapPointers")
  1682    && call.Uses == 1
  1683    && ssa.Clobber(call)
  1684    => (Zero {types.Types[types.TUINT8]} [int64(c)] sptr mem)
  1685  
  1686  // Recognise make([]T, 0) and replace it with a pointer to the zerobase
  1687  (StaticLECall {callAux} _ (Const(64|32) [0]) (Const(64|32) [0]) mem)
  1688  	&& ssa.IsSameCall(callAux, "runtime.makeslice")
  1689  	=> (MakeResult (Addr <v.Type.FieldType(0)> {ir.Syms.Zerobase} (SB)) mem)
  1690  
  1691  // Evaluate constant address comparisons.
  1692  (EqPtr  x x) => (ConstBool [true])
  1693  (NeqPtr x x) => (ConstBool [false])
  1694  (EqPtr  (Addr {x} _) (Addr {y} _)) => (ConstBool [x == y])
  1695  (EqPtr  (Addr {x} _) (OffPtr [o] (Addr {y} _))) => (ConstBool [x == y && o == 0])
  1696  (EqPtr  (OffPtr [o1] (Addr {x} _)) (OffPtr [o2] (Addr {y} _))) => (ConstBool [x == y && o1 == o2])
  1697  (NeqPtr (Addr {x} _) (Addr {y} _)) => (ConstBool [x != y])
  1698  (NeqPtr (Addr {x} _) (OffPtr [o] (Addr {y} _))) => (ConstBool [x != y || o != 0])
  1699  (NeqPtr (OffPtr [o1] (Addr {x} _)) (OffPtr [o2] (Addr {y} _))) => (ConstBool [x != y || o1 != o2])
  1700  (EqPtr  (LocalAddr {x} _ _) (LocalAddr {y} _ _)) => (ConstBool [x == y])
  1701  (EqPtr  (LocalAddr {x} _ _) (OffPtr [o] (LocalAddr {y} _ _))) => (ConstBool [x == y && o == 0])
  1702  (EqPtr  (OffPtr [o1] (LocalAddr {x} _ _)) (OffPtr [o2] (LocalAddr {y} _ _))) => (ConstBool [x == y && o1 == o2])
  1703  (NeqPtr (LocalAddr {x} _ _) (LocalAddr {y} _ _)) => (ConstBool [x != y])
  1704  (NeqPtr (LocalAddr {x} _ _) (OffPtr [o] (LocalAddr {y} _ _))) => (ConstBool [x != y || o != 0])
  1705  (NeqPtr (OffPtr [o1] (LocalAddr {x} _ _)) (OffPtr [o2] (LocalAddr {y} _ _))) => (ConstBool [x != y || o1 != o2])
  1706  (EqPtr  (OffPtr [o1] p1) p2) && ssa.IsSamePtr(p1, p2) => (ConstBool [o1 == 0])
  1707  (NeqPtr (OffPtr [o1] p1) p2) && ssa.IsSamePtr(p1, p2) => (ConstBool [o1 != 0])
  1708  (EqPtr  (OffPtr [o1] p1) (OffPtr [o2] p2)) && ssa.IsSamePtr(p1, p2) => (ConstBool [o1 == o2])
  1709  (NeqPtr (OffPtr [o1] p1) (OffPtr [o2] p2)) && ssa.IsSamePtr(p1, p2) => (ConstBool [o1 != o2])
  1710  (EqPtr  (Const(32|64) [c]) (Const(32|64) [d])) => (ConstBool [c == d])
  1711  (NeqPtr (Const(32|64) [c]) (Const(32|64) [d])) => (ConstBool [c != d])
  1712  (EqPtr  (Convert (Addr {x} _) _) (Addr {y} _)) => (ConstBool [x==y])
  1713  (NeqPtr (Convert (Addr {x} _) _) (Addr {y} _)) => (ConstBool [x!=y])
  1714  
  1715  (EqPtr  (LocalAddr _ _) (Addr _)) => (ConstBool [false])
  1716  (EqPtr  (OffPtr (LocalAddr _ _)) (Addr _)) => (ConstBool [false])
  1717  (EqPtr  (LocalAddr _ _) (OffPtr (Addr _))) => (ConstBool [false])
  1718  (EqPtr  (OffPtr (LocalAddr _ _)) (OffPtr (Addr _))) => (ConstBool [false])
  1719  (NeqPtr (LocalAddr _ _) (Addr _)) => (ConstBool [true])
  1720  (NeqPtr (OffPtr (LocalAddr _ _)) (Addr _)) => (ConstBool [true])
  1721  (NeqPtr (LocalAddr _ _) (OffPtr (Addr _))) => (ConstBool [true])
  1722  (NeqPtr (OffPtr (LocalAddr _ _)) (OffPtr (Addr _))) => (ConstBool [true])
  1723  
  1724  // Simplify address comparisons.
  1725  (EqPtr  (AddPtr p1 o1) p2) && ssa.IsSamePtr(p1, p2) => (Not (IsNonNil o1))
  1726  (NeqPtr (AddPtr p1 o1) p2) && ssa.IsSamePtr(p1, p2) => (IsNonNil o1)
  1727  (EqPtr  (Const(32|64) [0]) p) => (Not (IsNonNil p))
  1728  (NeqPtr (Const(32|64) [0]) p) => (IsNonNil p)
  1729  (EqPtr  (ConstNil) p) => (Not (IsNonNil p))
  1730  (NeqPtr (ConstNil) p) => (IsNonNil p)
  1731  
  1732  // Evaluate constant user nil checks.
  1733  (IsNonNil (ConstNil)) => (ConstBool [false])
  1734  (IsNonNil (Const(32|64) [c])) => (ConstBool [c != 0])
  1735  (IsNonNil          (Addr _)   ) => (ConstBool [true])
  1736  (IsNonNil (Convert (Addr _) _)) => (ConstBool [true])
  1737  (IsNonNil (LocalAddr _ _)) => (ConstBool [true])
  1738  
  1739  // Inline small or disjoint runtime.memmove calls with constant length.
  1740  // See the comment in op Move in genericOps.go for discussion of the type.
  1741  //
  1742  // Note that we've lost any knowledge of the type and alignment requirements
  1743  // of the source and destination. We only know the size, and that the type
  1744  // contains no pointers.
  1745  // The type of the move is not necessarily v.Args[0].Type().Elem()!
  1746  // See issue 55122 for details.
  1747  //
  1748  // Because expand calls runs after prove, constants useful to this pattern may not appear.
  1749  // Both versions need to exist; the memory and register variants.
  1750  //
  1751  // Match post-expansion calls, memory version.
  1752  (SelectN [0] call:(StaticCall {sym} s1:(Store _ (Const(64|32) [sz]) s2:(Store  _ src s3:(Store {t} _ dst mem)))))
  1753  	&& sz >= 0
  1754  	&& ssa.IsSameCall(sym, "runtime.memmove")
  1755  	&& s1.Uses == 1 && s2.Uses == 1 && s3.Uses == 1
  1756  	&& ssa.IsInlinableMemmove(dst, src, int64(sz), config)
  1757  	&& ssa.Clobber(s1, s2, s3, call)
  1758  	=> (Move {types.Types[types.TUINT8]} [int64(sz)] dst src mem)
  1759  
  1760  // Match post-expansion calls, register version.
  1761  (SelectN [0] call:(StaticCall {sym} dst src (Const(64|32) [sz]) mem))
  1762  	&& sz >= 0
  1763  	&& call.Uses == 1 // this will exclude all calls with results
  1764  	&& ssa.IsSameCall(sym, "runtime.memmove")
  1765  	&& ssa.IsInlinableMemmove(dst, src, int64(sz), config)
  1766  	&& ssa.Clobber(call)
  1767  	=> (Move {types.Types[types.TUINT8]} [int64(sz)] dst src mem)
  1768  
  1769  // Match pre-expansion calls.
  1770  (SelectN [0] call:(StaticLECall {sym} dst src (Const(64|32) [sz]) mem))
  1771  	&& sz >= 0
  1772  	&& call.Uses == 1 // this will exclude all calls with results
  1773  	&& ssa.IsSameCall(sym, "runtime.memmove")
  1774  	&& ssa.IsInlinableMemmove(dst, src, int64(sz), config)
  1775  	&& ssa.Clobber(call)
  1776  	=> (Move {types.Types[types.TUINT8]} [int64(sz)] dst src mem)
  1777  
  1778  // De-virtualize late-expanded interface calls into late-expanded static calls.
  1779  (InterLECall [argsize] {auxCall} (Addr {fn} (SB)) ___) => devirtLECall(v, fn.(*obj.LSym))
  1780  
  1781  // Move and Zero optimizations.
  1782  // Move source and destination may overlap.
  1783  
  1784  // Convert Moves into Zeros when the source is known to be zeros.
  1785  (Move {t} [n] dst1 src mem:(Zero {t} [n] dst2 _)) && ssa.IsSamePtr(src, dst2)
  1786  	=> (Zero {t} [n] dst1 mem)
  1787  (Move {t} [n] dst1 src mem:(VarDef (Zero {t} [n] dst0 _))) && ssa.IsSamePtr(src, dst0)
  1788  	=> (Zero {t} [n] dst1 mem)
  1789  (Move {t} [n] dst (Addr {sym} (SB)) mem) && symIsROZero(sym) => (Zero {t} [n] dst mem)
  1790  
  1791  // Don't Store to variables that are about to be overwritten by Move/Zero.
  1792  (Zero {t1} [n] p1 store:(Store {t2} (OffPtr [o2] p2) _ mem))
  1793  	&& ssa.IsSamePtr(p1, p2) && store.Uses == 1
  1794  	&& n >= o2 + t2.Size()
  1795  	&& ssa.Clobber(store)
  1796  	=> (Zero {t1} [n] p1 mem)
  1797  (Move {t1} [n] dst1 src1 store:(Store {t2} op1:(OffPtr [o2] dst2) _ mem))
  1798  	&& ssa.IsSamePtr(dst1, dst2) && store.Uses == 1
  1799  	&& n >= o2 + t2.Size()
  1800  	&& ssa.Disjoint1(src1, n, op1, t2.Size())
  1801  	&& ssa.Clobber(store)
  1802  	=> (Move {t1} [n] dst1 src1 mem)
  1803  
  1804  // Don't Move to variables that are immediately completely overwritten.
  1805  (Zero {t} [n] dst1 move:(Move {t} [n] dst2 _ mem))
  1806  	&& move.Uses == 1
  1807  	&& ssa.IsSamePtr(dst1, dst2)
  1808  	&& ssa.Clobber(move)
  1809  	=> (Zero {t} [n] dst1 mem)
  1810  (Move {t} [n] dst1 src1 move:(Move {t} [n] dst2 _ mem))
  1811  	&& move.Uses == 1
  1812  	&& ssa.IsSamePtr(dst1, dst2) && ssa.Disjoint1(src1, n, dst2, n)
  1813  	&& ssa.Clobber(move)
  1814  	=> (Move {t} [n] dst1 src1 mem)
  1815  (Zero {t} [n] dst1 vardef:(VarDef {x} move:(Move {t} [n] dst2 _ mem)))
  1816  	&& move.Uses == 1 && vardef.Uses == 1
  1817  	&& ssa.IsSamePtr(dst1, dst2)
  1818  	&& ssa.Clobber(move, vardef)
  1819  	=> (Zero {t} [n] dst1 (VarDef {x} mem))
  1820  (Move {t} [n] dst1 src1 vardef:(VarDef {x} move:(Move {t} [n] dst2 _ mem)))
  1821  	&& move.Uses == 1 && vardef.Uses == 1
  1822  	&& ssa.IsSamePtr(dst1, dst2) && ssa.Disjoint1(src1, n, dst2, n)
  1823  	&& ssa.Clobber(move, vardef)
  1824  	=> (Move {t} [n] dst1 src1 (VarDef {x} mem))
  1825  (Store {t1} op1:(OffPtr [o1] p1) d1
  1826  	m2:(Store {t2} op2:(OffPtr [0] p2) d2
  1827  		m3:(Move [n] p3 _ mem)))
  1828  	&& m2.Uses == 1 && m3.Uses == 1
  1829  	&& o1 == t2.Size()
  1830  	&& n == t2.Size() + t1.Size()
  1831  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3)
  1832  	&& ssa.Clobber(m2, m3)
  1833  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 mem))
  1834  (Store {t1} op1:(OffPtr [o1] p1) d1
  1835  	m2:(Store {t2} op2:(OffPtr [o2] p2) d2
  1836  		m3:(Store {t3} op3:(OffPtr [0] p3) d3
  1837  			m4:(Move [n] p4 _ mem))))
  1838  	&& m2.Uses == 1 && m3.Uses == 1 && m4.Uses == 1
  1839  	&& o2 == t3.Size()
  1840  	&& o1-o2 == t2.Size()
  1841  	&& n == t3.Size() + t2.Size() + t1.Size()
  1842  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4)
  1843  	&& ssa.Clobber(m2, m3, m4)
  1844  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 (Store {t3} op3 d3 mem)))
  1845  (Store {t1} op1:(OffPtr [o1] p1) d1
  1846  	m2:(Store {t2} op2:(OffPtr [o2] p2) d2
  1847  		m3:(Store {t3} op3:(OffPtr [o3] p3) d3
  1848  			m4:(Store {t4} op4:(OffPtr [0] p4) d4
  1849  				m5:(Move [n] p5 _ mem)))))
  1850  	&& m2.Uses == 1 && m3.Uses == 1 && m4.Uses == 1 && m5.Uses == 1
  1851  	&& o3 == t4.Size()
  1852  	&& o2-o3 == t3.Size()
  1853  	&& o1-o2 == t2.Size()
  1854  	&& n == t4.Size() + t3.Size() + t2.Size() + t1.Size()
  1855  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4) && ssa.IsSamePtr(p4, p5)
  1856  	&& ssa.Clobber(m2, m3, m4, m5)
  1857  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 (Store {t3} op3 d3 (Store {t4} op4 d4 mem))))
  1858  
  1859  // Don't Zero variables that are immediately completely overwritten
  1860  // before being accessed.
  1861  (Move {t} [n] dst1 src1 zero:(Zero {t} [n] dst2 mem))
  1862  	&& zero.Uses == 1
  1863  	&& ssa.IsSamePtr(dst1, dst2) && ssa.Disjoint1(src1, n, dst2, n)
  1864  	&& ssa.Clobber(zero)
  1865  	=> (Move {t} [n] dst1 src1 mem)
  1866  (Move {t} [n] dst1 src1 vardef:(VarDef {x} zero:(Zero {t} [n] dst2 mem)))
  1867  	&& zero.Uses == 1 && vardef.Uses == 1
  1868  	&& ssa.IsSamePtr(dst1, dst2) && ssa.Disjoint1(src1, n, dst2, n)
  1869  	&& ssa.Clobber(zero, vardef)
  1870  	=> (Move {t} [n] dst1 src1 (VarDef {x} mem))
  1871  (Store {t1} op1:(OffPtr [o1] p1) d1
  1872  	m2:(Store {t2} op2:(OffPtr [0] p2) d2
  1873  		m3:(Zero [n] p3 mem)))
  1874  	&& m2.Uses == 1 && m3.Uses == 1
  1875  	&& o1 == t2.Size()
  1876  	&& n == t2.Size() + t1.Size()
  1877  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3)
  1878  	&& ssa.Clobber(m2, m3)
  1879  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 mem))
  1880  (Store {t1} op1:(OffPtr [o1] p1) d1
  1881  	m2:(Store {t2} op2:(OffPtr [o2] p2) d2
  1882  		m3:(Store {t3} op3:(OffPtr [0] p3) d3
  1883  			m4:(Zero [n] p4 mem))))
  1884  	&& m2.Uses == 1 && m3.Uses == 1 && m4.Uses == 1
  1885  	&& o2 == t3.Size()
  1886  	&& o1-o2 == t2.Size()
  1887  	&& n == t3.Size() + t2.Size() + t1.Size()
  1888  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4)
  1889  	&& ssa.Clobber(m2, m3, m4)
  1890  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 (Store {t3} op3 d3 mem)))
  1891  (Store {t1} op1:(OffPtr [o1] p1) d1
  1892  	m2:(Store {t2} op2:(OffPtr [o2] p2) d2
  1893  		m3:(Store {t3} op3:(OffPtr [o3] p3) d3
  1894  			m4:(Store {t4} op4:(OffPtr [0] p4) d4
  1895  				m5:(Zero [n] p5 mem)))))
  1896  	&& m2.Uses == 1 && m3.Uses == 1 && m4.Uses == 1 && m5.Uses == 1
  1897  	&& o3 == t4.Size()
  1898  	&& o2-o3 == t3.Size()
  1899  	&& o1-o2 == t2.Size()
  1900  	&& n == t4.Size() + t3.Size() + t2.Size() + t1.Size()
  1901  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4) && ssa.IsSamePtr(p4, p5)
  1902  	&& ssa.Clobber(m2, m3, m4, m5)
  1903  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 (Store {t3} op3 d3 (Store {t4} op4 d4 mem))))
  1904  
  1905  // Don't Move from memory if the values are likely to already be
  1906  // in registers.
  1907  (Move {t1} [n] dst p1
  1908  	mem:(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  1909  		(Store {t3} op3:(OffPtr <tt3> [0] p3) d2 _)))
  1910  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3)
  1911  	&& t2.Alignment() <= t1.Alignment()
  1912  	&& t3.Alignment() <= t1.Alignment()
  1913  	&& registerizable(b, t2)
  1914  	&& registerizable(b, t3)
  1915  	&& o2 == t3.Size()
  1916  	&& n == t2.Size() + t3.Size()
  1917  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  1918  		(Store {t3} (OffPtr <tt3> [0] dst) d2 mem))
  1919  (Move {t1} [n] dst p1
  1920  	mem:(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  1921  		(Store {t3} op3:(OffPtr <tt3> [o3] p3) d2
  1922  			(Store {t4} op4:(OffPtr <tt4> [0] p4) d3 _))))
  1923  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4)
  1924  	&& t2.Alignment() <= t1.Alignment()
  1925  	&& t3.Alignment() <= t1.Alignment()
  1926  	&& t4.Alignment() <= t1.Alignment()
  1927  	&& registerizable(b, t2)
  1928  	&& registerizable(b, t3)
  1929  	&& registerizable(b, t4)
  1930  	&& o3 == t4.Size()
  1931  	&& o2-o3 == t3.Size()
  1932  	&& n == t2.Size() + t3.Size() + t4.Size()
  1933  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  1934  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  1935  			(Store {t4} (OffPtr <tt4> [0] dst) d3 mem)))
  1936  (Move {t1} [n] dst p1
  1937  	mem:(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  1938  		(Store {t3} op3:(OffPtr <tt3> [o3] p3) d2
  1939  			(Store {t4} op4:(OffPtr <tt4> [o4] p4) d3
  1940  				(Store {t5} op5:(OffPtr <tt5> [0] p5) d4 _)))))
  1941  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4) && ssa.IsSamePtr(p4, p5)
  1942  	&& t2.Alignment() <= t1.Alignment()
  1943  	&& t3.Alignment() <= t1.Alignment()
  1944  	&& t4.Alignment() <= t1.Alignment()
  1945  	&& t5.Alignment() <= t1.Alignment()
  1946  	&& registerizable(b, t2)
  1947  	&& registerizable(b, t3)
  1948  	&& registerizable(b, t4)
  1949  	&& registerizable(b, t5)
  1950  	&& o4 == t5.Size()
  1951  	&& o3-o4 == t4.Size()
  1952  	&& o2-o3 == t3.Size()
  1953  	&& n == t2.Size() + t3.Size() + t4.Size() + t5.Size()
  1954  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  1955  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  1956  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  1957  				(Store {t5} (OffPtr <tt5> [0] dst) d4 mem))))
  1958  
  1959  // Same thing but with VarDef in the middle.
  1960  (Move {t1} [n] dst p1
  1961  	mem:(VarDef
  1962  		(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  1963  			(Store {t3} op3:(OffPtr <tt3> [0] p3) d2 _))))
  1964  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3)
  1965  	&& t2.Alignment() <= t1.Alignment()
  1966  	&& t3.Alignment() <= t1.Alignment()
  1967  	&& registerizable(b, t2)
  1968  	&& registerizable(b, t3)
  1969  	&& o2 == t3.Size()
  1970  	&& n == t2.Size() + t3.Size()
  1971  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  1972  		(Store {t3} (OffPtr <tt3> [0] dst) d2 mem))
  1973  (Move {t1} [n] dst p1
  1974  	mem:(VarDef
  1975  		(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  1976  			(Store {t3} op3:(OffPtr <tt3> [o3] p3) d2
  1977  				(Store {t4} op4:(OffPtr <tt4> [0] p4) d3 _)))))
  1978  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4)
  1979  	&& t2.Alignment() <= t1.Alignment()
  1980  	&& t3.Alignment() <= t1.Alignment()
  1981  	&& t4.Alignment() <= t1.Alignment()
  1982  	&& registerizable(b, t2)
  1983  	&& registerizable(b, t3)
  1984  	&& registerizable(b, t4)
  1985  	&& o3 == t4.Size()
  1986  	&& o2-o3 == t3.Size()
  1987  	&& n == t2.Size() + t3.Size() + t4.Size()
  1988  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  1989  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  1990  			(Store {t4} (OffPtr <tt4> [0] dst) d3 mem)))
  1991  (Move {t1} [n] dst p1
  1992  	mem:(VarDef
  1993  		(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  1994  			(Store {t3} op3:(OffPtr <tt3> [o3] p3) d2
  1995  				(Store {t4} op4:(OffPtr <tt4> [o4] p4) d3
  1996  					(Store {t5} op5:(OffPtr <tt5> [0] p5) d4 _))))))
  1997  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4) && ssa.IsSamePtr(p4, p5)
  1998  	&& t2.Alignment() <= t1.Alignment()
  1999  	&& t3.Alignment() <= t1.Alignment()
  2000  	&& t4.Alignment() <= t1.Alignment()
  2001  	&& t5.Alignment() <= t1.Alignment()
  2002  	&& registerizable(b, t2)
  2003  	&& registerizable(b, t3)
  2004  	&& registerizable(b, t4)
  2005  	&& registerizable(b, t5)
  2006  	&& o4 == t5.Size()
  2007  	&& o3-o4 == t4.Size()
  2008  	&& o2-o3 == t3.Size()
  2009  	&& n == t2.Size() + t3.Size() + t4.Size() + t5.Size()
  2010  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2011  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2012  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2013  				(Store {t5} (OffPtr <tt5> [0] dst) d4 mem))))
  2014  
  2015  // Prefer to Zero and Store than to Move.
  2016  (Move {t1} [n] dst p1
  2017  	mem:(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2018  		(Zero {t3} [n] p3 _)))
  2019  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3)
  2020  	&& t2.Alignment() <= t1.Alignment()
  2021  	&& t3.Alignment() <= t1.Alignment()
  2022  	&& registerizable(b, t2)
  2023  	&& n >= o2 + t2.Size()
  2024  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2025  		(Zero {t1} [n] dst mem))
  2026  (Move {t1} [n] dst p1
  2027  	mem:(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2028  		(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2029  			(Zero {t4} [n] p4 _))))
  2030  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4)
  2031  	&& t2.Alignment() <= t1.Alignment()
  2032  	&& t3.Alignment() <= t1.Alignment()
  2033  	&& t4.Alignment() <= t1.Alignment()
  2034  	&& registerizable(b, t2)
  2035  	&& registerizable(b, t3)
  2036  	&& n >= o2 + t2.Size()
  2037  	&& n >= o3 + t3.Size()
  2038  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2039  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2040  			(Zero {t1} [n] dst mem)))
  2041  (Move {t1} [n] dst p1
  2042  	mem:(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2043  		(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2044  			(Store {t4} (OffPtr <tt4> [o4] p4) d3
  2045  				(Zero {t5} [n] p5 _)))))
  2046  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4) && ssa.IsSamePtr(p4, p5)
  2047  	&& t2.Alignment() <= t1.Alignment()
  2048  	&& t3.Alignment() <= t1.Alignment()
  2049  	&& t4.Alignment() <= t1.Alignment()
  2050  	&& t5.Alignment() <= t1.Alignment()
  2051  	&& registerizable(b, t2)
  2052  	&& registerizable(b, t3)
  2053  	&& registerizable(b, t4)
  2054  	&& n >= o2 + t2.Size()
  2055  	&& n >= o3 + t3.Size()
  2056  	&& n >= o4 + t4.Size()
  2057  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2058  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2059  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2060  				(Zero {t1} [n] dst mem))))
  2061  (Move {t1} [n] dst p1
  2062  	mem:(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2063  		(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2064  			(Store {t4} (OffPtr <tt4> [o4] p4) d3
  2065  				(Store {t5} (OffPtr <tt5> [o5] p5) d4
  2066  					(Zero {t6} [n] p6 _))))))
  2067  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4) && ssa.IsSamePtr(p4, p5) && ssa.IsSamePtr(p5, p6)
  2068  	&& t2.Alignment() <= t1.Alignment()
  2069  	&& t3.Alignment() <= t1.Alignment()
  2070  	&& t4.Alignment() <= t1.Alignment()
  2071  	&& t5.Alignment() <= t1.Alignment()
  2072  	&& t6.Alignment() <= t1.Alignment()
  2073  	&& registerizable(b, t2)
  2074  	&& registerizable(b, t3)
  2075  	&& registerizable(b, t4)
  2076  	&& registerizable(b, t5)
  2077  	&& n >= o2 + t2.Size()
  2078  	&& n >= o3 + t3.Size()
  2079  	&& n >= o4 + t4.Size()
  2080  	&& n >= o5 + t5.Size()
  2081  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2082  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2083  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2084  				(Store {t5} (OffPtr <tt5> [o5] dst) d4
  2085  					(Zero {t1} [n] dst mem)))))
  2086  (Move {t1} [n] dst p1
  2087  	mem:(VarDef
  2088  		(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2089  			(Zero {t3} [n] p3 _))))
  2090  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3)
  2091  	&& t2.Alignment() <= t1.Alignment()
  2092  	&& t3.Alignment() <= t1.Alignment()
  2093  	&& registerizable(b, t2)
  2094  	&& n >= o2 + t2.Size()
  2095  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2096  		(Zero {t1} [n] dst mem))
  2097  (Move {t1} [n] dst p1
  2098  	mem:(VarDef
  2099  		(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2100  			(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2101  				(Zero {t4} [n] p4 _)))))
  2102  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4)
  2103  	&& t2.Alignment() <= t1.Alignment()
  2104  	&& t3.Alignment() <= t1.Alignment()
  2105  	&& t4.Alignment() <= t1.Alignment()
  2106  	&& registerizable(b, t2)
  2107  	&& registerizable(b, t3)
  2108  	&& n >= o2 + t2.Size()
  2109  	&& n >= o3 + t3.Size()
  2110  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2111  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2112  			(Zero {t1} [n] dst mem)))
  2113  (Move {t1} [n] dst p1
  2114  	mem:(VarDef
  2115  		(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2116  			(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2117  				(Store {t4} (OffPtr <tt4> [o4] p4) d3
  2118  					(Zero {t5} [n] p5 _))))))
  2119  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4) && ssa.IsSamePtr(p4, p5)
  2120  	&& t2.Alignment() <= t1.Alignment()
  2121  	&& t3.Alignment() <= t1.Alignment()
  2122  	&& t4.Alignment() <= t1.Alignment()
  2123  	&& t5.Alignment() <= t1.Alignment()
  2124  	&& registerizable(b, t2)
  2125  	&& registerizable(b, t3)
  2126  	&& registerizable(b, t4)
  2127  	&& n >= o2 + t2.Size()
  2128  	&& n >= o3 + t3.Size()
  2129  	&& n >= o4 + t4.Size()
  2130  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2131  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2132  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2133  				(Zero {t1} [n] dst mem))))
  2134  (Move {t1} [n] dst p1
  2135  	mem:(VarDef
  2136  		(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2137  			(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2138  				(Store {t4} (OffPtr <tt4> [o4] p4) d3
  2139  					(Store {t5} (OffPtr <tt5> [o5] p5) d4
  2140  						(Zero {t6} [n] p6 _)))))))
  2141  	&& ssa.IsSamePtr(p1, p2) && ssa.IsSamePtr(p2, p3) && ssa.IsSamePtr(p3, p4) && ssa.IsSamePtr(p4, p5) && ssa.IsSamePtr(p5, p6)
  2142  	&& t2.Alignment() <= t1.Alignment()
  2143  	&& t3.Alignment() <= t1.Alignment()
  2144  	&& t4.Alignment() <= t1.Alignment()
  2145  	&& t5.Alignment() <= t1.Alignment()
  2146  	&& t6.Alignment() <= t1.Alignment()
  2147  	&& registerizable(b, t2)
  2148  	&& registerizable(b, t3)
  2149  	&& registerizable(b, t4)
  2150  	&& registerizable(b, t5)
  2151  	&& n >= o2 + t2.Size()
  2152  	&& n >= o3 + t3.Size()
  2153  	&& n >= o4 + t4.Size()
  2154  	&& n >= o5 + t5.Size()
  2155  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2156  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2157  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2158  				(Store {t5} (OffPtr <tt5> [o5] dst) d4
  2159  					(Zero {t1} [n] dst mem)))))
  2160  
  2161  (SelectN [0] call:(StaticLECall {sym} a x)) && needRaceCleanup(sym, call) && ssa.Clobber(call) => x
  2162  (SelectN [0] call:(StaticLECall {sym} x)) && needRaceCleanup(sym, call) && ssa.Clobber(call) => x
  2163  
  2164  // When rewriting append to growslice, we use as the new length the result of
  2165  // growslice so that we don't have to spill/restore the new length around the growslice call.
  2166  // The exception here is that if the new length is a constant, avoiding spilling it
  2167  // is pointless and its constantness is sometimes useful for subsequent optimizations.
  2168  // See issue 56440.
  2169  // Note there are 2 rules here, one for the pre-decomposed []T result and one for
  2170  // the post-decomposed (*T,int,int) result. (The latter is generated after call expansion.)
  2171  // TODO(thepudds): we probably need the new growsliceBuf and growsliceBufNoAlias here as well?
  2172  (SliceLen (SelectN [0] (StaticLECall {sym} _ newLen:(Const(64|32)) _ _ _ _)))
  2173  	&& (ssa.IsSameCall(sym, "runtime.growslice") || ssa.IsSameCall(sym, "runtime.growsliceNoAlias"))
  2174  	=> newLen
  2175  (SelectN [1] (StaticCall {sym} _ newLen:(Const(64|32)) _ _ _ _)) && v.Type.IsInteger()
  2176  	&& (ssa.IsSameCall(sym, "runtime.growslice") || ssa.IsSameCall(sym, "runtime.growsliceNoAlias"))
  2177  	=> newLen
  2178  
  2179  // Collapse moving A -> B -> C into just A -> C.
  2180  // Later passes (deadstore, elim unread auto) will remove the A -> B move, if possible.
  2181  // This happens most commonly when B is an autotmp inserted earlier
  2182  // during compilation to ensure correctness.
  2183  // Take care that overlapping moves are preserved.
  2184  // Restrict this optimization to the stack, to avoid duplicating loads from the heap;
  2185  // see CL 145208 for discussion.
  2186  (Move {t1} [s] dst tmp1 midmem:(Move {t2} [s] tmp2 src _))
  2187  	&& t1.Compare(t2) == types.CMPeq
  2188  	&& ssa.IsSamePtr(tmp1, tmp2)
  2189  	&& isStackPtr(src) && !ssa.IsVolatile(src)
  2190  	&& ssa.Disjoint1(src, s, tmp2, s)
  2191  	&& (ssa.Disjoint1(src, s, dst, s) || ssa.IsInlinableMemmove(dst, src, s, config))
  2192  	=> (Move {t1} [s] dst src midmem)
  2193  
  2194  // Same, but for large types that require VarDefs.
  2195  (Move {t1} [s] dst tmp1 midmem:(VarDef (Move {t2} [s] tmp2 src _)))
  2196  	&& t1.Compare(t2) == types.CMPeq
  2197  	&& ssa.IsSamePtr(tmp1, tmp2)
  2198  	&& isStackPtr(src) && !ssa.IsVolatile(src)
  2199  	&& ssa.Disjoint1(src, s, tmp2, s)
  2200  	&& (ssa.Disjoint1(src, s, dst, s) || ssa.IsInlinableMemmove(dst, src, s, config))
  2201  	=> (Move {t1} [s] dst src midmem)
  2202  
  2203  // Don't zero the same bits twice.
  2204  (Zero {t} [s] dst1 zero:(Zero {t} [s] dst2 _)) && ssa.IsSamePtr(dst1, dst2) => zero
  2205  (Zero {t} [s] dst1 vardef:(VarDef (Zero {t} [s] dst2 _))) && ssa.IsSamePtr(dst1, dst2) => vardef
  2206  
  2207  // Elide self-moves. This only happens rarely (e.g test/fixedbugs/bug277.go).
  2208  // However, this rule is needed to prevent the previous rule from looping forever in such cases.
  2209  (Move dst src mem) && ssa.IsSamePtr(dst, src) => mem
  2210  
  2211  // Constant rotate detection.
  2212  ((Add64|Or64|Xor64) (Lsh64x64 x z:(Const64 <t> [c])) (Rsh64Ux64 x (Const64 [d]))) && c < 64 && d == 64-c && canRotate(config, 64) => (RotateLeft64 x z)
  2213  ((Add32|Or32|Xor32) (Lsh32x64 x z:(Const64 <t> [c])) (Rsh32Ux64 x (Const64 [d]))) && c < 32 && d == 32-c && canRotate(config, 32) => (RotateLeft32 x z)
  2214  ((Add16|Or16|Xor16) (Lsh16x64 x z:(Const64 <t> [c])) (Rsh16Ux64 x (Const64 [d]))) && c < 16 && d == 16-c && canRotate(config, 16) => (RotateLeft16 x z)
  2215  ((Add8|Or8|Xor8) (Lsh8x64 x z:(Const64 <t> [c])) (Rsh8Ux64 x (Const64 [d]))) && c < 8 && d == 8-c && canRotate(config, 8) => (RotateLeft8 x z)
  2216  
  2217  // Non-constant rotate detection.
  2218  // We use shiftIsBounded to make sure that neither of the shifts are >64.
  2219  // Note: these rules are subtle when the shift amounts are 0/64, as Go shifts
  2220  // are different from most native shifts. But it works out.
  2221  ((Add64|Or64|Xor64) left:(Lsh64x64 x y) right:(Rsh64Ux64 x (Sub64 (Const64 [64]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x y)
  2222  ((Add64|Or64|Xor64) left:(Lsh64x32 x y) right:(Rsh64Ux32 x (Sub32 (Const32 [64]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x y)
  2223  ((Add64|Or64|Xor64) left:(Lsh64x16 x y) right:(Rsh64Ux16 x (Sub16 (Const16 [64]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x y)
  2224  ((Add64|Or64|Xor64) left:(Lsh64x8  x y) right:(Rsh64Ux8  x (Sub8  (Const8  [64]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x y)
  2225  
  2226  ((Add64|Or64|Xor64) right:(Rsh64Ux64 x y) left:(Lsh64x64 x z:(Sub64 (Const64 [64]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x z)
  2227  ((Add64|Or64|Xor64) right:(Rsh64Ux32 x y) left:(Lsh64x32 x z:(Sub32 (Const32 [64]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x z)
  2228  ((Add64|Or64|Xor64) right:(Rsh64Ux16 x y) left:(Lsh64x16 x z:(Sub16 (Const16 [64]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x z)
  2229  ((Add64|Or64|Xor64) right:(Rsh64Ux8  x y) left:(Lsh64x8  x z:(Sub8  (Const8  [64]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x z)
  2230  
  2231  ((Add32|Or32|Xor32) left:(Lsh32x64 x y) right:(Rsh32Ux64 x (Sub64 (Const64 [32]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x y)
  2232  ((Add32|Or32|Xor32) left:(Lsh32x32 x y) right:(Rsh32Ux32 x (Sub32 (Const32 [32]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x y)
  2233  ((Add32|Or32|Xor32) left:(Lsh32x16 x y) right:(Rsh32Ux16 x (Sub16 (Const16 [32]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x y)
  2234  ((Add32|Or32|Xor32) left:(Lsh32x8  x y) right:(Rsh32Ux8  x (Sub8  (Const8  [32]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x y)
  2235  
  2236  ((Add32|Or32|Xor32) right:(Rsh32Ux64 x y) left:(Lsh32x64 x z:(Sub64 (Const64 [32]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x z)
  2237  ((Add32|Or32|Xor32) right:(Rsh32Ux32 x y) left:(Lsh32x32 x z:(Sub32 (Const32 [32]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x z)
  2238  ((Add32|Or32|Xor32) right:(Rsh32Ux16 x y) left:(Lsh32x16 x z:(Sub16 (Const16 [32]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x z)
  2239  ((Add32|Or32|Xor32) right:(Rsh32Ux8  x y) left:(Lsh32x8  x z:(Sub8  (Const8  [32]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x z)
  2240  
  2241  ((Add16|Or16|Xor16) left:(Lsh16x64 x y) right:(Rsh16Ux64 x (Sub64 (Const64 [16]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x y)
  2242  ((Add16|Or16|Xor16) left:(Lsh16x32 x y) right:(Rsh16Ux32 x (Sub32 (Const32 [16]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x y)
  2243  ((Add16|Or16|Xor16) left:(Lsh16x16 x y) right:(Rsh16Ux16 x (Sub16 (Const16 [16]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x y)
  2244  ((Add16|Or16|Xor16) left:(Lsh16x8  x y) right:(Rsh16Ux8  x (Sub8  (Const8  [16]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x y)
  2245  
  2246  ((Add16|Or16|Xor16) right:(Rsh16Ux64 x y) left:(Lsh16x64 x z:(Sub64 (Const64 [16]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x z)
  2247  ((Add16|Or16|Xor16) right:(Rsh16Ux32 x y) left:(Lsh16x32 x z:(Sub32 (Const32 [16]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x z)
  2248  ((Add16|Or16|Xor16) right:(Rsh16Ux16 x y) left:(Lsh16x16 x z:(Sub16 (Const16 [16]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x z)
  2249  ((Add16|Or16|Xor16) right:(Rsh16Ux8  x y) left:(Lsh16x8  x z:(Sub8  (Const8  [16]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x z)
  2250  
  2251  ((Add8|Or8|Xor8) left:(Lsh8x64 x y) right:(Rsh8Ux64 x (Sub64 (Const64 [8]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x y)
  2252  ((Add8|Or8|Xor8) left:(Lsh8x32 x y) right:(Rsh8Ux32 x (Sub32 (Const32 [8]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x y)
  2253  ((Add8|Or8|Xor8) left:(Lsh8x16 x y) right:(Rsh8Ux16 x (Sub16 (Const16 [8]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x y)
  2254  ((Add8|Or8|Xor8) left:(Lsh8x8  x y) right:(Rsh8Ux8  x (Sub8  (Const8  [8]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x y)
  2255  
  2256  ((Add8|Or8|Xor8) right:(Rsh8Ux64 x y) left:(Lsh8x64 x z:(Sub64 (Const64 [8]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x z)
  2257  ((Add8|Or8|Xor8) right:(Rsh8Ux32 x y) left:(Lsh8x32 x z:(Sub32 (Const32 [8]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x z)
  2258  ((Add8|Or8|Xor8) right:(Rsh8Ux16 x y) left:(Lsh8x16 x z:(Sub16 (Const16 [8]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x z)
  2259  ((Add8|Or8|Xor8) right:(Rsh8Ux8  x y) left:(Lsh8x8  x z:(Sub8  (Const8  [8]) y))) && (ssa.ShiftIsBounded(left) || ssa.ShiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x z)
  2260  
  2261  // Rotating by y&c, with c a mask that doesn't change the bottom bits, is the same as rotating by y.
  2262  (RotateLeft64 x (And(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&63 == 63 => (RotateLeft64 x y)
  2263  (RotateLeft32 x (And(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&31 == 31 => (RotateLeft32 x y)
  2264  (RotateLeft16 x (And(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&15 == 15 => (RotateLeft16 x y)
  2265  (RotateLeft8  x (And(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&7  == 7  => (RotateLeft8  x y)
  2266  
  2267  // Rotating by -(y&c), with c a mask that doesn't change the bottom bits, is the same as rotating by -y.
  2268  (RotateLeft64 x (Neg(64|32|16|8) (And(64|32|16|8) y (Const(64|32|16|8) [c])))) && c&63 == 63 => (RotateLeft64 x (Neg(64|32|16|8) <y.Type> y))
  2269  (RotateLeft32 x (Neg(64|32|16|8) (And(64|32|16|8) y (Const(64|32|16|8) [c])))) && c&31 == 31 => (RotateLeft32 x (Neg(64|32|16|8) <y.Type> y))
  2270  (RotateLeft16 x (Neg(64|32|16|8) (And(64|32|16|8) y (Const(64|32|16|8) [c])))) && c&15 == 15 => (RotateLeft16 x (Neg(64|32|16|8) <y.Type> y))
  2271  (RotateLeft8  x (Neg(64|32|16|8) (And(64|32|16|8) y (Const(64|32|16|8) [c])))) && c&7  == 7  => (RotateLeft8  x (Neg(64|32|16|8) <y.Type> y))
  2272  
  2273  // Rotating by y+c, with c a multiple of the value width, is the same as rotating by y.
  2274  (RotateLeft64 x (Add(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&63 == 0 => (RotateLeft64 x y)
  2275  (RotateLeft32 x (Add(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&31 == 0 => (RotateLeft32 x y)
  2276  (RotateLeft16 x (Add(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&15 == 0 => (RotateLeft16 x y)
  2277  (RotateLeft8  x (Add(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&7  == 0 => (RotateLeft8  x y)
  2278  
  2279  // Rotating by c-y, with c a multiple of the value width, is the same as rotating by -y.
  2280  (RotateLeft64 x (Sub(64|32|16|8) (Const(64|32|16|8) [c]) y)) && c&63 == 0 => (RotateLeft64 x (Neg(64|32|16|8) <y.Type> y))
  2281  (RotateLeft32 x (Sub(64|32|16|8) (Const(64|32|16|8) [c]) y)) && c&31 == 0 => (RotateLeft32 x (Neg(64|32|16|8) <y.Type> y))
  2282  (RotateLeft16 x (Sub(64|32|16|8) (Const(64|32|16|8) [c]) y)) && c&15 == 0 => (RotateLeft16 x (Neg(64|32|16|8) <y.Type> y))
  2283  (RotateLeft8  x (Sub(64|32|16|8) (Const(64|32|16|8) [c]) y)) && c&7  == 0 => (RotateLeft8  x (Neg(64|32|16|8) <y.Type> y))
  2284  
  2285  // Ensure we don't do Const64 rotates in a 32-bit system.
  2286  (RotateLeft64 x (Const64 <t> [c])) && config.PtrSize == 4 => (RotateLeft64 x (Const32 <t> [int32(c)]))
  2287  (RotateLeft32 x (Const64 <t> [c])) && config.PtrSize == 4 => (RotateLeft32 x (Const32 <t> [int32(c)]))
  2288  (RotateLeft16 x (Const64 <t> [c])) && config.PtrSize == 4 => (RotateLeft16 x (Const32 <t> [int32(c)]))
  2289  (RotateLeft8  x (Const64 <t> [c])) && config.PtrSize == 4 => (RotateLeft8  x (Const32 <t> [int32(c)]))
  2290  
  2291  // Rotating by c, then by d, is the same as rotating by c+d.
  2292  // We're trading a rotate for an add, which seems generally a good choice. It is especially good when c and d are constants.
  2293  // This rule is a bit tricky as c and d might be different widths. We handle only cases where they are the same width.
  2294  (RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 8 && d.Type.Size() == 8 => (RotateLeft(64|32|16|8) x (Add64 <c.Type> c d))
  2295  (RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 4 && d.Type.Size() == 4 => (RotateLeft(64|32|16|8) x (Add32 <c.Type> c d))
  2296  (RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 2 && d.Type.Size() == 2 => (RotateLeft(64|32|16|8) x (Add16 <c.Type> c d))
  2297  (RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 1 && d.Type.Size() == 1 => (RotateLeft(64|32|16|8) x (Add8  <c.Type> c d))
  2298  
  2299  // Loading fixed addresses and constants.
  2300  (Load                                     (Addr {s} sb)         _)  && isFixedLoad(v, s,   0) => rewriteFixedLoad(v, s, sb,   0)
  2301  (Load                            (Convert (Addr {s} sb) _)      _)  && isFixedLoad(v, s,   0) => rewriteFixedLoad(v, s, sb,   0)
  2302  (Load               (ITab (IMake          (Addr {s} sb)    _))  _)  && isFixedLoad(v, s,   0) => rewriteFixedLoad(v, s, sb,   0)
  2303  (Load               (ITab (IMake (Convert (Addr {s} sb) _) _))  _)  && isFixedLoad(v, s,   0) => rewriteFixedLoad(v, s, sb,   0)
  2304  (Load (OffPtr [off]                       (Addr {s} sb)       ) _)  && isFixedLoad(v, s, off) => rewriteFixedLoad(v, s, sb, off)
  2305  (Load (OffPtr [off]              (Convert (Addr {s} sb) _)    ) _)  && isFixedLoad(v, s, off) => rewriteFixedLoad(v, s, sb, off)
  2306  (Load (OffPtr [off] (ITab (IMake          (Addr {s} sb)    _))) _)  && isFixedLoad(v, s, off) => rewriteFixedLoad(v, s, sb, off)
  2307  (Load (OffPtr [off] (ITab (IMake (Convert (Addr {s} sb) _) _))) _)  && isFixedLoad(v, s, off) => rewriteFixedLoad(v, s, sb, off)
  2308  
  2309  // Calling cmpstring a second time with the same arguments in the
  2310  // same memory state can reuse the results of the first call.
  2311  // See issue 61725.
  2312  // Note that this could pretty easily generalize to any pure function.
  2313  (SelectN [0] (StaticLECall {f} x y (SelectN [1] c:(StaticLECall {g} x y mem))))
  2314    && ssa.IsSameCall(f, "runtime.cmpstring")
  2315    && ssa.IsSameCall(g, "runtime.cmpstring")
  2316  => @c.Block (SelectN [0] <typ.Int> c)
  2317  
  2318  // If we don't use the result of cmpstring, might as well not call it.
  2319  // Note that this could pretty easily generalize to any pure function.
  2320  (SelectN [1] c:(StaticLECall {f} _ _ mem)) && c.Uses == 1 && ssa.IsSameCall(f, "runtime.cmpstring") && ssa.Clobber(c) => mem
  2321  
  2322  // We can easily compute the result of efaceeq if
  2323  // we know the underlying type is pointer-ish.
  2324  (StaticLECall {f} typ_ x y mem)
  2325  	&& ssa.IsSameCall(f, "runtime.efaceeq")
  2326  	&& isDirectAndComparableType(typ_)
  2327  	&& ssa.Clobber(v)
  2328  	=> (MakeResult (EqPtr x y) mem)
  2329  
  2330  // We can easily compute the result of ifaceeq if
  2331  // we know the underlying type is pointer-ish.
  2332  (StaticLECall {f} itab x y mem)
  2333  	&& ssa.IsSameCall(f, "runtime.ifaceeq")
  2334  	&& isDirectAndComparableIface(itab)
  2335  	&& ssa.Clobber(v)
  2336  	=> (MakeResult (EqPtr x y) mem)
  2337  
  2338  // If we use the result of slicebytetostring in a map lookup operation,
  2339  // then we don't need to actually do the []byte->string conversion.
  2340  // We can just use the ptr/len of the byte slice directly as a (temporary) string.
  2341  //
  2342  // Note that this does not handle some obscure cases like
  2343  // m[[2]string{string(b1), string(b2)}]. There is code in ../walk/order.go
  2344  // which handles some of those cases.
  2345  (StaticLECall {f} [argsize] typ_ map_ key:(SelectN [0] sbts:(StaticLECall {g} _ ptr len mem)) m:(SelectN [1] sbts))
  2346    &&    (ssa.IsSameCall(f, "runtime.mapaccess1_faststr")
  2347        || ssa.IsSameCall(f, "runtime.mapaccess2_faststr")
  2348        || ssa.IsSameCall(f, "runtime.mapdelete_faststr"))
  2349    && ssa.IsSameCall(g, "runtime.slicebytetostring")
  2350    && key.Uses == 1
  2351    && sbts.Uses == 2
  2352    && resetCopy(m, mem)
  2353    && ssa.Clobber(sbts)
  2354    && ssa.Clobber(key)
  2355  => (StaticLECall {f} [argsize] typ_ map_ (StringMake <typ.String> ptr len) mem)
  2356  
  2357  // Similarly to map lookups, also handle unique.Make for strings, which unique.Make will clone.
  2358  (StaticLECall {f} [argsize] dict_ key:(SelectN [0] sbts:(StaticLECall {g} _ ptr len mem)) m:(SelectN [1] sbts))
  2359    && ssa.IsSameCall(f, "unique.Make[go.shape.string]")
  2360    && ssa.IsSameCall(g, "runtime.slicebytetostring")
  2361    && key.Uses == 1
  2362    && sbts.Uses == 2
  2363    && resetCopy(m, mem)
  2364    && ssa.Clobber(sbts)
  2365    && ssa.Clobber(key)
  2366  => (StaticLECall {f} [argsize] dict_ (StringMake <typ.String> ptr len) mem)
  2367  
  2368  // Transform some CondSelect into math operations.
  2369  // if b { x += c } => x += b * c
  2370  (CondSelect op1:(Add8 <t> x c:(Const8)) x bool) &&
  2371  	rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) =>
  2372  	(Add8 x (Mul8 <t> c (CvtBoolToUint8 <t> bool)))
  2373  (CondSelect op1:(Add(64|32|16) <t> x c:(Const(64|32|16))) x bool) &&
  2374  	rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) =>
  2375  	(Add(64|32|16) x (Mul(64|32|16) <t> c (ZeroExt8to(64|32|16) <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> bool))))
  2376  // if !b { x += c } => x += !b * c
  2377  (CondSelect x op1:(Add8 <t> x c:(Const8)) bool) &&
  2378  	rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) =>
  2379  	(Add8 x (Mul8 <t> c (CvtBoolToUint8 <t> (Not <bool.Type> bool))))
  2380  (CondSelect x op1:(Add(64|32|16) <t> x c:(Const(64|32|16))) bool) &&
  2381  	rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) =>
  2382  	(Add(64|32|16) x (Mul(64|32|16) <t> c (ZeroExt8to(64|32|16) <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> (Not <bool.Type> bool)))))
  2383  
  2384  // if b { x += c } => x -= b * -c // looks redundant but useful if the arch can inline materialize -c but not c
  2385  (CondSelect op1:(Add8 <t> x c:(Const8 [consT])) x bool) &&
  2386  	!rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) &&
  2387  	rewriteCondSelectIntoMath(config, addToSub(op1.Op), -c.AuxInt) =>
  2388  	(Sub8 x (Mul8 <t> (Const8 <t> [-consT]) (CvtBoolToUint8 <t> bool)))
  2389  (CondSelect op1:(Add(64|32|16) <t> x c:(Const(64|32|16) [consT])) x bool) &&
  2390  	!rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) &&
  2391  	rewriteCondSelectIntoMath(config, addToSub(op1.Op), -c.AuxInt) =>
  2392  	(Sub(64|32|16) x (Mul(64|32|16) <t> (Const(64|32|16) <t> [-consT]) (ZeroExt8to(64|32|16) <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> bool))))
  2393  // if !b { x += c } => x -= !b * -c // looks redundant but useful if the arch can inline materialize -c but not c
  2394  (CondSelect x op1:(Add8 <t> x c:(Const8 [consT])) bool) &&
  2395  	!rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) &&
  2396  	rewriteCondSelectIntoMath(config, addToSub(op1.Op), -c.AuxInt) =>
  2397  	(Sub8 x (Mul8 <t> (Const8 <t> [-consT]) (CvtBoolToUint8 <t> (Not <bool.Type> bool))))
  2398  (CondSelect x op1:(Add(64|32|16) <t> x c:(Const(64|32|16) [consT])) bool) &&
  2399  	!rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) &&
  2400  	rewriteCondSelectIntoMath(config, addToSub(op1.Op), -c.AuxInt) =>
  2401  	(Sub(64|32|16) x (Mul(64|32|16) <t> (Const(64|32|16) <t> [-consT]) (ZeroExt8to(64|32|16) <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> (Not <bool.Type> bool)))))
  2402  
  2403  // if b { x <<= 1 } => x <<= b
  2404  (CondSelect (Lsh(64|32|16|8)x64 x (Const64 [1])) x bool) => (Lsh(64|32|16|8)x8 [true] x (CvtBoolToUint8 <types.Types[types.TUINT8]> bool))
  2405  // if !b { x <<= 1 } => x <<= !b
  2406  (CondSelect x (Lsh(64|32|16|8)x64 x (Const64 [1])) bool) => (Lsh(64|32|16|8)x8 [true] x (CvtBoolToUint8 <types.Types[types.TUINT8]> (Not <bool.Type> bool)))
  2407  
  2408  // if b { x >>= 1 } => x >>= b
  2409  (CondSelect (Rsh(64|32|16|8)x64 x (Const64 [1])) x bool) => (Rsh(64|32|16|8)x8 [true] x (CvtBoolToUint8 <types.Types[types.TUINT8]> bool))
  2410  (CondSelect (Rsh(64|32|16|8)Ux64 x (Const64 [1])) x bool) => (Rsh(64|32|16|8)Ux8 [true] x (CvtBoolToUint8 <types.Types[types.TUINT8]> bool))
  2411  // if !b { x >>= 1 } => x >>= !b
  2412  (CondSelect x (Rsh(64|32|16|8)x64 x (Const64 [1])) bool) => (Rsh(64|32|16|8)x8 [true] x (CvtBoolToUint8 <types.Types[types.TUINT8]> (Not <bool.Type> bool)))
  2413  (CondSelect x (Rsh(64|32|16|8)Ux64 x (Const64 [1])) bool) => (Rsh(64|32|16|8)Ux8 [true] x (CvtBoolToUint8 <types.Types[types.TUINT8]> (Not <bool.Type> bool)))
  2414  
  2415  // if b { x |= c } => x |= b * c
  2416  (CondSelect op1:(Or8 <t> x c:(Const8)) x bool) &&
  2417  	rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) =>
  2418  	(Or8 x (Mul8 <t> c (CvtBoolToUint8 <t> bool)))
  2419  (CondSelect op1:(Or(64|32|16) <t> x c:(Const(64|32|16))) x bool) &&
  2420  	rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) =>
  2421  	(Or(64|32|16) x (Mul(64|32|16) <t> c (ZeroExt8to(64|32|16) <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> bool))))
  2422  // if !b { x |= c } => x |= !b * c
  2423  (CondSelect x op1:(Or8 <t> x c:(Const8)) bool) &&
  2424  	rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) =>
  2425  	(Or8 x (Mul8 <t> c (CvtBoolToUint8 <t> (Not <bool.Type> bool))))
  2426  (CondSelect x op1:(Or(64|32|16) <t> x c:(Const(64|32|16))) bool) &&
  2427  	rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) =>
  2428  	(Or(64|32|16) x (Mul(64|32|16) <t> c (ZeroExt8to(64|32|16) <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> (Not <bool.Type> bool)))))
  2429  
  2430  // if b { x ^= c } => x ^= b * c
  2431  (CondSelect op1:(Xor8 <t> x c:(Const8)) x bool) &&
  2432  	rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) =>
  2433  	(Xor8 x (Mul8 <t> c (CvtBoolToUint8 <t> bool)))
  2434  (CondSelect op1:(Xor(64|32|16) <t> x c:(Const(64|32|16))) x bool) &&
  2435  	rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) =>
  2436  	(Xor(64|32|16) x (Mul(64|32|16) <t> c (ZeroExt8to(64|32|16) <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> bool))))
  2437  // if !b { x ^= c } => x ^= !b * c
  2438  (CondSelect x op1:(Xor8 <t> x c:(Const8)) bool) &&
  2439  	rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) =>
  2440  	(Xor8 x (Mul8 <t> c (CvtBoolToUint8 <t> (Not <bool.Type> bool))))
  2441  (CondSelect x op1:(Xor(64|32|16) <t> x c:(Const(64|32|16))) bool) &&
  2442  	rewriteCondSelectIntoMath(config, op1.Op, c.AuxInt) =>
  2443  	(Xor(64|32|16) x (Mul(64|32|16) <t> c (ZeroExt8to(64|32|16) <t> (CvtBoolToUint8 <types.Types[types.TUINT8]> (Not <bool.Type> bool)))))
  2444  
  2445  // bool(int(x)) => x
  2446  (Neq8                                (CvtBoolToUint8 x)  (Const8          [0])) => x
  2447  (Neq8                                (CvtBoolToUint8 x)  (Const8          [1])) => (Not x)
  2448  (Eq8                                 (CvtBoolToUint8 x)  (Const8          [1])) => x
  2449  (Eq8                                 (CvtBoolToUint8 x)  (Const8          [0])) => (Not x)
  2450  (Neq(64|32|16) (ZeroExt8to(64|32|16) (CvtBoolToUint8 x)) (Const(64|32|16) [0])) => x
  2451  (Neq(64|32|16) (ZeroExt8to(64|32|16) (CvtBoolToUint8 x)) (Const(64|32|16) [1])) => (Not x)
  2452  (Eq(64|32|16)  (ZeroExt8to(64|32|16) (CvtBoolToUint8 x)) (Const(64|32|16) [1])) => x
  2453  (Eq(64|32|16)  (ZeroExt8to(64|32|16) (CvtBoolToUint8 x)) (Const(64|32|16) [0])) => (Not x)
  2454  
  2455  // Canonicalize sext(int(bool)) => zext(int(bool))
  2456  (SignExt8to(64|32|16) cvt:(CvtBoolToUint8 bool)) => (ZeroExt8to(64|32|16) cvt)
  2457  
  2458  // int(bool)^1 => int(!bool)
  2459  (Xor8                                (CvtBoolToUint8        bool)  (Const8 [1]))          && invertibleBool(bool.Op) =>                       (CvtBoolToUint8        (Not <bool.Type> bool))
  2460  (Xor(64|32|16) (ZeroExt8to(64|32|16) (CvtBoolToUint8 <cvtT> bool)) (Const(64|32|16) [1])) && invertibleBool(bool.Op) => (ZeroExt8to(64|32|16) (CvtBoolToUint8 <cvtT> (Not <bool.Type> bool)))
  2461  
  2462  // int(!bool)^c => int(bool)^(c^1)
  2463  (Xor8                                (CvtBoolToUint8 <cvtT> (Not bool))  (Const8          <constT> [c])) && c != 1 => (Xor8                                (CvtBoolToUint8 <cvtT> bool)  (Const8          <constT> [c^1]))
  2464  (Xor(64|32|16) (ZeroExt8to(64|32|16) (CvtBoolToUint8 <cvtT> (Not bool))) (Const(64|32|16) <constT> [c])) && c != 1 => (Xor(64|32|16) (ZeroExt8to(64|32|16) (CvtBoolToUint8 <cvtT> bool)) (Const(64|32|16) <constT> [c^1]))
  2465  

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